Your credit card issuer doesn't care about charges for hosting fees, SSL, or Fiverr -- those may be crypto-related to you, but they aren't to your bank. Your bank just sees them as web services, freelancing, etc.
When they see you charging credit to buy bitcoins through Simplex, that's a very different type of activity, which is prohibited by the bank.
OP's own words.
Yepp, credit cards that I used with no problem for at least 1 year to purchase BTC
Maybe OP hadn't used it in a while as it's been blocked since June 2019 -
https://www.investopedia.com/news/capital-one-blocks-cryptocurrency-purchases-its-card/And they blocked Coinbase buys at the start of 2018 but I dunno if that changed.
I can't imagine they slipped through the cracks until now so something's getting lost in translation.