Been getting a bit pissed off with Firefox being so resource-hungry, so I’ve now switched to Brave as my main browser and been very impressed by it. The Firefox extensions I use are all working fine, and page loading times seem much better.
I’ve also ditched Opera as it can be very sluggish on start-up: giving Comodo IceDragon a try instead as a lightweight “test” browser.
UPDATE: And gave up with IceDragon to move to FlashPeak SlimBrowser: generally fast, and clears cookies and cache on exit.