A gravel bike, unless you want something specific, is a great place to save some $$. Most of the AL bikes are going to just as good as the higher end bikes when you slap fat tires on them. Most options are great options, so get the best paint job. Most of the fancy suspension features that aren’t actually suspension, aren’t much better than just a good seat post (looking at German mag Tour Int frame tests on a testing jig Example ) save a few bikes (specifically the 2022 Trek Checkpoint SL/SLR, which looks to be 2x as complaint as the next best bike).
There are two kinds of gravel bikes now… 1) mostly road bike (‘racing’ / ‘all road’) and 2) mostly adventure bike. They mostly do the same thing the same way; the differences are the seating positions and the number of accessory mounts. If you’re going to going on mostly groomed paths, “all road bikes” (Trek Domane) and new “cyclocross bikes” (Specialized Crux, Trek Boone, Cannondale something…) take 38-40c tires and make good road bikes too.On the adventure side, these are anything from the Canyon Grail to some steel Surly camping bike.
On the sub-$2k AL bikes, you usually need to replace the seat post with a softer riding one (example Trek ALR 5 - Bontrager Comp, 6061 alloy is tear worthy stiff with road tires at 100psi; a good CF one twice as compliant) and the tires (which are always slow rolling on stock bikes). The frames are usually the same weight and modern, hydroformed AL bikes ride the same as CF ones. 10sp and 11sp speed aren’t that much different in the real world, but you’ll want 11sp if you have an 11sp road bike. AL is a bit nicer to scrape up.
At the $3k price point, the Trek Checkpoint SL and Canyon bikes standout ( because of the fancy seat posts; The Giant offering with the D-shaped seat post and the Specialized Diverge is probably going to be right there, but I haven’t looked at the #s). The Trek specifically has frame-storage is nice if you’re going to be bringing 2-spare tubes and some emergency gear regularly. If you’re going to be hitting bumps bigger than a redbull can, you might want to look into bikes with a front suspension solution and/or a longer frontend (most of the newer bikes are 20cm longer than a standard road bike and use a 20cm shorter stem, these bikes will take 45c+ tires) to help stop you from going over the handlebars when you hit a bump.
There are some suspension bikes out there, but you’re looking at a least another grand. Some of the big brand stock wheels may fall apart on you, but they’ll last a few years even if they are prone to doing that. I’d get 10,11, or 12speed because of the bigger gear ranges.I’d have you save $1k on an AL bike and spend that money on a couple of bags/tires/bars/seatpost/saddle, etc. Get something with 3-water bottle mounts, but the top tube/fork/etc mounts aren’t necessary in most cases. Otherwise, you really can’t make a bad choice here - other than spending too much money and not getting the right paint job.