Can not track back my Bitcoin purchases

Hey guys. I started to buy Bitcoin back in 2019. I registered many sites/wallets/exchanges. I do not remember where I bought what. I had no emails or transaction history. I handled it chaotically back than.

Eventually I moved everything on one wallet and did not touched for years.

My question is this can be an issue when I cash out? I mean tax-wise. Since I can not prove buying price and origin of the coins?

I am a UK resident.

Any advise and help welcome.