Some suggestions in no particular order. You might be aware of some of these but I’m going to try to assume no or almost no prior knowledge.

• After you buy a camera, you’ll start investing body in lenses. You will want to upgrade your body at some point, but probably you wouldn’t want that to mean you have to replace all your lenses. So try to find out what is your “dream” camera and buy the “baby” version of that, so that you get an upgrade path that is compatible with all/most lenses that you end up buying. E.g. Sony A6100 -> A7IV -> A9 Look up the style of photography people use these cameras for, pros and cons… You’re buying into a system, not just a camera. Switching is doable but expensive, so it’s good to get this right first time.
• IF you don’t mind manual focusing (that’s a big if), you can find really nice (vintage) lenses for peanuts on eBay that you can use on your camera with an adapter. This advice used to be more relevant when DSLRs were more prominent, as you had to make sure the flange distance would let you adapt all lenses, but in the age of mirrorless pretty much any camera has adapters for pretty much any vintage system. Do check this though - it’s useful unless you’re completely against the idea of focusing manually.
• If you go the route of vintage lenses, one feature that will make your life a lot easier is IBIS (in-body image stabilization). It basically means that the sensor is on a stabilised mount (not quite a gimbal but picture that) and you can take photos with longer focal lengths handheld.
• Prime lenses (non-zoom, the ones that only have a single focal length) tend to have much better performance than zoom lenses at the same price point. The problem is that you have to know you like that focal length before you buy them. Buy something that comes with a zoom lens and use it at fixed focal lengths (e.g. only shoot 50mm for a day) to see what you enjoy. You can also do try this with your phone.
• At least while you’re starting, embrace second hand. You can buy and sell lenses on eBay or similar losing very little money, so that’s a great way to try gear when you’re not sure you’ll like it.
• Lightroom is almost a standard but Darktable is free and against all odds, even more powerful than LR. I’d recommend getting started with it (or with RawTherapee) so you don’t have to pile up software costs on top of the camera.
• Try to shoot RAW as much as possible. Many modern cameras will produce great JPEGs straight out of the camera, Fujis are particularly good in this regard. However RAW files give you far broader possibilities to edit them to achieve what you want, which means that A) they’re more forgiving when you’re starting out and B) by editing and “fixing” your mistakes in post you’ll learn quickly what’s wrong with your pictures.
• Learn / research what crop factor is. The short version is focal lengths are usually referred in “35mm equivalent”, I.e. the focal length that would give you an equivalent field of view on a traditional 35mm camera. If you have a bigger sensor, the same focal length will look more “zoomed out” as the extra “periphery” of the bigger sensor will be covering more surface, if that makes sense. They’re a useful tool to compare the field of view across lenses / cameras with different sensors.
• Don’t listen to snobs - sure, you can get great photos more easily with a £5k camera but when you’re starting out you don’t need that. Save your money for when you know what you need. E.g. are you craving more resolution because you shoot architecture, or better low light performance because you’ve discovered you really enjoy concert photography? Sony (sorry for being so sony-centric, it’s the brand I know about the most) has the A7R and the A7S ranges which offer radically different capabilities, and neither is better, just geared for different uses. It’s better to start with a cheaper jack-of-all trades until you have a really good reason to spend more money on a body upgrade, as you’re really unlikely to get it exactly right early on.