Brave. I also like Vivaldi, but it's not fully open source. Firefox is a no go due to their open support of censorship.
Solus Plasma, fresh restart after updates, only uses 700mb of ram. Only things that are currently running is Steam 350mb and Brave with 3 tabs, (27 Brave related processes) ~ 750mb of ram usage. 1,7gb used out of 32gb.