>>4265834That is probably the second most expensive rabbit hole in all of photography
If you are very cheap, budget for a zoom camera like an rx10iii/rx10iv, nikon coolpix p900/p1000, etc, there are a lot of these and they are generally around $1k or less. These have similar quality to micro four thirds for most situations and cover a wide zoom range, but do not have much bokeh because the lenses at their fastest are like, f/8 equivalent. They fall apart in dim light pretty fast.
If you have more money and want a little more bokeys and slightly better low light performance, then you need to start looking at the great deals in micro four thirds, like the olympus e-m1 II/III and lumix gh5/gh6, and lenses around 200mm or 300mm. 400mm (800mm equivalent) may seem nice but isn't considered necessary by most wildlife shooters and ups the price considerably. You will probably end up spending $1000-$2000 with your body, your wildlife zoom, and a general purpose lens. Cheaper bodies exist, but it gets worse fast, micro four thirds was intended to be a consumer system, an alternative to phones. Don't overspend either, the newer ones haven't gotten practically better (framerates the AF cant really keep up with, and amateur cinema features, that's it). The point of buying m43 is to budget and lighten. You still lose quality.
If you are not so cheap and like bigger stuff, budget for an APS-C camera and any ok zoom that maxes out around 300mm or 400mm. You will probably end up spending $2000 or more for mirrorless, but you can trim costs by using a DSLR, which is going to be bulkier for everything else and a little harder to use. The canon R7 is the best mirrorless and the 90d is the best DSLR for this class. You can save money here by adapting EF lenses.
Fuji may look tempting, but they are overpriced. a gh6 with good post processing will outdo your average fuji really..
If you are rich and like carrying giant cameras, or just insist on FF quality... nikon Z 180-600.