Sharding unlike in Ethereum wouldn't work well with Bitcoin
Bitcoin design focuses more on simplicity and security and introducing sharding Would complicate things
And affect security
Not to mention Bitcoin makes use of POW not POS and uses a linear chain model
Introducing sharding would increase the risk of decentralization.

Bitcoin already makes use of offchain transactions via layer 2 like Lightning network.

pre-emphasis: scaling means increments.. not leaping to huge stupid numbers instantly(the propaganda made to stifle discussion of scaling)

when the core devs themselves know 4mb of data is network safe for 8 years now and even that is below todays amount that could be network safe
that 4mb of space could be refined to actually allow more transactions per block by removing the cludgy code that miscounts bytes and bypasses validations to allow bloated junk..
this alone could allow upto 28tx/s

moving the 4mb up to a newer number could allow even more transactions too..
also there are ways to actually make transactions leaner in a true every byte counted and validated way.

and to anyone about to scream "cost of hard drives would kill decentralisation"
the fact that we have not surpassed the 7tx/s estimate first talked about in 2010 is where we have become more popular and yet not allowed for the growth since 2017, which is where people end up moving to other networks thus less people willing to decentralise the blockchain
also with dev-politics thinking they are economists and beleive that $20-$100 per tx fee is the acceptable amount people should/could pay now and in near future.. a $70 hard drive can and will store all 15 years of tx history and a decade more.. so its not a hard drive problem that will deter people if there were more tx on the bitcoin blockchain

so in short, yes we can scale bitcoin without having to push people over to other networks/chains/payment systems (that are not about confirming a tx to bitcoins blockchain)