@digdeeper I did some testing with Furryfox and Iridium, both with no tabs open, and measured using btop.

I got the following:
Furryfox
threads: 164+31+28+19+19+19+6 = 267
mem: 414M+148M+125M+85M+85M+85M+54M = 996 MiB

Iridium
threads: 34+37+22+22+22+21+21+21+9+19+1+1+4+1+2+1 = 238
mem: 206M+187M+114M+104M+103M+101M+96M+94M+74M+61M+58M+56M+32M+15M+6.2M+4.6M = 1312 MiB

So I can't say that Furryfox is a bigger memory hog than Iridium.
And Furryfox is still with all the telemetry enabled, mind you (I installed it specifically for this test).