Is using vivaldi instead of chrome considered degoogling? I have heard that it uses chromium as its engine, but I want to know whats the downside of that? Does it diretcly bring money to google by using a chromium based browser? Does google somehow collect data from it?
No, if you are using a chromium browser you are using chrome. to some extent or another google is involved. The level of googles involvemnet is different per browser but if you want to elimnate them completly you will probably need some obscure firefox fork. Even then without something like no script blocking googles servers almost every site will collect google analytics.
The best general use Firefox forks are Librewolf and Waterfox.
Using any chromium engine based browser skews the market share to Google. The greater percentage of pages viewed with chromium, the more sites and designers go all in with Google. The device fingerprinting and tracking is one of Google’s big lock in money makers.
Getting as many people as possible off chromium engine browsers is positive for the web in general.