If you don't know about the technical aspects of Bitcoin, then you can ask experienced users in a community like this for the best recommendations for those that are open source and those that are not. This is why this forum was created to share and discuss Bitcoin; then we can also pick up a challenge to learn over time in order to know how we can increase our knowledge about Bitcoin's technical aspects and be able to do some findings independently.

With the suggestions about another brand of HW to be trusted. I think that the worry remains there despite that there will be more audits and volunteer developers to check their open source codes.

The best practice for the non technical holders is to split the holdings you have.

Maybe do it like this;

30% in the HW(Trezor, etc.)
30% in Electrum
20% in Blue wallet
20% up to you, but not with exchanges.

So this is just an example allotment but you do you.

I am not against the practice of splitting bitcoins into different wallets it’s one of the most secure means of storing your bitcoins but that is subjected to if you can handle the redundancy of storing your seed phrases and also possibly passphrase because they must not be stored in same place and you still need to have more than one back up for each seed phrase at different locations, this is where redundancy comes in.

For this your setup though I am not comfortable with it, you have total of 50% of the coin in electrum and BlueWallet to which both are actually hot wallet except you wish to run them as cold wallet, if not halve of your holdings already is online and will have one point of failure which is your device, once it gets compromised both wallet can be affected on that device 

This is a terrible suggestion that doesn't really fix the issue. You just replaced ColdCard with Electrum. If a critical vulnerability or flaw were found in Electrum instead of the ColdCard firmware, you'd end up facing the exact same outcome. 


So you don't trust hardware wallets and their developers, but you trust Electrum software? Can you explain why?

The random number generator used by Ledger is a hardware true random generator that was evaluated by third-party labs and holds an EAL5+ and AIS-31 security certification. Ledger hardware wallets use a custom-built operating system named Ledger OS and I seriously doubt they'd be stupid enough, like Coldcard apparently was, to also include an unreliable software random generator. A True Random Number Generator (TRNG) works by capturing unpredictable physical noise from the environment—such as thermal noise, atmospheric noise, or oscillator jitter—and converting it into digital bits rather than using a math formula.

The problem with Coldcard was a bug that - instead of using true hardware-based randomness - an incorrect macro check caused the device to fall back to a predictable software pseudorandom number generator (Yasmarang) seeded only by non-secret chip data and system timers. Having any fallback to a non-hardware RNG is insane and it's just crazy that open source reviewers failed to catch this, but hackers clearly found it.

Use Electrum wallet, create a single signature wallet with a passphrase, or if want more security, creating a multisig wallet. It's not hard to create a single signature wallet with a passphrase (custom words).

When creating a wallet, click on Options and choose "Extend this seed with custom words".
Type the custom words you want, and you have to back up (write down) both wallet seed words and your custom words.

Next step will be typing and confirming both seed words and custom words, before creating a wallet password.

Some guides to use Electrum wallet.
Creating an Electrum wallet.
Creating a cold storage wallet in Electrum.
Creating a multisig wallet in Electrum.

I second that stance on Ledger. I hate that company with a passion for several reasons.
They had some major f-ups in the past: Their user-data got leaked exposing over one million e-mail addresses and associated names and address info of people that purchased Ledger wallets.
See https://haveibeenpwned.com/Breach/Ledger

Also their feature to restore a wallet is extremely shady and was criticized by the whole Bitcoin-sphere.

Open-source plus long-lasting flaw-less reputation is a good indicator for a decent HW wallet. There is no guarantee for safety, though.

Older Trezor-wallets were hacked in the past, however afaik it does need physical access to the Trezor device.

My comparison of Electrum wallet with ColdCard software is merely to point out that no software is entirely immune to bugs or flaws. even open-source giants with amazing dev communities like Electrum.

But you actually make a fair point for beginners holding a modest funds, a battle-tested software wallet like Electrum on a secure, clean device, combined with a properly backed-up seed phrase can be totally reasonable.

If we were to compare the differences between these two wallets, it really comes down to radically different approaches to open-source and transparency. Electrum operates under standard, OSI-approved open-source licenses. Anyone can fork, inspect, modify, host, or re-distribute the code without restriction. A true Open Source. Because it is used as the codebase for countless wallet integrations, and thousands of independent developers regularly fork, test, compile, and stress-test the code.

Coldcard, on the other hand, has the "source available" facade. They transitioned their firmware to a proprietary license with a commons clause. This prevented independent developers from using their code, commercially or non-commercially. Because of this, developers outside of Coinkite had little incentive to actually build with, maintain, or deeply test the firmware.

This is exactly what brought them to their doom, in my opinion. The sheer arrogance and poor licensing decisions of their founder and CEO, Rodolfo Novak (aka nvK).

Just keep it simple and use Electrum and backup your wallet to a flashdrive. Keep it simple.