If you switch your recieving address for each different signature campaing (for example) then after years you will have a lot of different addresses with payments.
I suppose yes, although I don't think a user will switch campaigns too often. They definitely will, but I think that most users stick to a campaign for some months.
So you would need to find a way to be able to pay with your bitcoin in a way that does not tie you to to your public addresses that have you shared here or elsewhere.
I wouldn't worry
too much about it, but my suggestions are:
(1) coinjoins
(2) swap for XMR and then back to BTC
(3) LN swaps
(4) Liquid BTC peg-in and peg-out
If I was worried that my funds from campaigns A (address X), B (address Y), C (address Z) were going to be linked and prove that they 're paid to the same person, I would simply do one of the above methods on each payment individually.
But I am not worried because it's public data that apogio has received money from campaigns A,B,C on addresses X,Y,Z.
The problem with mixing coins (all of these are a form of mixing basically) is that you receive funds from random sources, so when you deposit these funds into a KYC place, or someone that you paid deposits these funds into a KYC place, then their chainalysis systems may get triggered by something you received during the funds and now you have a problem, since the person you paid to may point to you as the previous owner of these funds. So if you pay someone for a product or service that requires you doxed or you pay in person, that is a risk there. I have not found a solution for this, you have to assume some risk of this happening if you use your BTC to pay for things that require you are doxed, or pay in person for some product.
As far as campaigns, im not sure but sometimes I think they barely last a month. So you may end up with a lot of different addresses with funds.
The problem of privacy with BTC remains since if BTC was like XMR, it would be worth much less, since it's just a black box that you cannot audit. But since it's so transparent, it could lead to problems if you are receiving funds from someone non-doxed (like someone that pays you for a sig campaign, you don't know where the funds come from) or you paying someone with those funds and then triggering some problem due chainalysis systems, or trying to gain privacy by mixing the coins which is a very reasonable practice, ending up in a problem when you pay for something.
Let's say you have 1 BTC from sig campaigns, and then 1 BTC is worth a million by 2030. "Cool, let's buy a house". But then you find out these funds trigger chainalysis when you try to liquidate them for fiat. You did nothing wrong but receive some funds, but now you have a problem that you have to solve if you want to use these funds for anything relevant.