Firefox still isn't a suitable Chrome replacement. Chrome may be beaconing half your browsing data back to Mountain View quietly in the background, but Firefox shoves its monetization strategy right in your face every time you open a new tab (Pocket, VPN ads, etc). Firefox is also drastically more complex in the UI and menus, and is missing a lot of UX niceties in the window and address bar itself (extra clicks to search all open tabs comes to mind). Mozilla has no one to blame but Mozilla for where Firefox isn't in terms of market share.
Search all open tabs in Firefox: prefix your search with "% " (percent followed by a space).
Or don't, and it'll probably be in the list of suggested results anyway.
(Unless you're using container tabs, in which case it'll only search open tabs in the current container, which is sometimes good but usually a nuisance.)
I much prefer Firefox's address bar search heuristics over Chrome's, but it definitely depends on your usage patterns. Firefox is very good at suggesting relevant things from my history, to the extent that I will gasp actually close tabs now and rely on search to rediscover them, rather than forever accumulating open tabs that I might want to get back to.
