Sure, I can, but it would be a hassle and I'm kind of comfortable with what I have now. The first thing that hit me when I tried to get back to firefox (a couple weeks ago) was actually the time to load a page. It felt long compared to what I am use to. Sure it's anecdotic, but I opened a game called factoryidle that ran capped at 200 fps on Brave, it was only at 70-80 fps on Firefox. The adblocker I had installed was also inferior to Brave's. I guess it may be due to some extensions or I don't know, but something was wrong and I didn't want to do the effort to fix it.
It's like I want to believe, but as you say, I'm too lazy. I will try Ungoogled Chromium since you recommand it.
If you use Brave News (to display a RSS feed), you get "news" about Brave's functionnalities. They appear as any other widget in your feed, but are marked as "Advertisement" on the upper right corner. Here is an example from my feed : https://imgur.com/a/RJV2Px2 .
Looks like it's not the case anymore, but when I opened a new tab, some time ago, I used to get ads from Binance or other cryptocurrencies exchanges displayed as "cards" on the right of the window. Right now, I only get "cards" showing about "Brave Talks" or rewards, but it used to be advertisement about other products, such as Binance or other cryptocurrency company.
I can't reproduce it right now, but some "new tab" backgrounds are (or were) also advertisement for crypto-related products.
There was also a controversy some time ago where they were injecting their own referral link when you typed a cryptocurrency exchange's URL on the search bar : https://www.androidpolice.com/2020/06/07/brave-browser-caught-adding-its-own-referral-codes-to-some-cryptcurrency-trading-sites/ . They stopped after it got viral.
At least they are tagging their ads as such, but it's weird how you can't block any of it when they decide it's there.