Router recommendation for newbie

Edit: forgot to mention that I’m based in Europe, which might be relevant for which devices are easily available.

Hi, I am a newbie looking for a new router, one where I can block ads and tracking (with AdGuard, PiHole or something similar), I can choose my own DNS, and hopefully tinker more once I learn more about routers and networks. I have a home server currently running only locally and would like to access it from outside my home, but I’m afraid of letting the door open to bots, hackers, etc.
I am currently using the router provided by my ISP, which has poor customization options and is also failing a lot lately (it loses internet connection at least once a week and needs restarting).

I have searched a bit around and I think something where I can install OpenWRT or other open source firmware would be good. On the OpenWRT forum I have seen recommended the GL·INet Flint 2 GL-MT6000 openwrt.org/toh/gl.inet/gl-mt6000. I also looked a bit more on GL·INet’s website and saw the GL·INet 3e (GL-BE6500) which has WiFi 7, and wondered if that could be a good upgrade, but seems it doesn’t support (yet) installing official OpenWRT.

As for me and my use case: I am comfortable with the Linux command line, my personal computer runs Linux and I have a home server running OpenMediaVault with a couple of services on Docker (Jellyfin, Navidrome, Radicale, Trilium, Calibre-Web, Wanderer), but I barely know anything about routers and networks. The router will serve to connect that server via Ethernet and use several devices (laptops, desktop PC, phones, tablets, AndroidTV…) via WiFi.

I wonder what the thoughts of people who know about routers and networks are.

• Are these good options for a first non-ISP router?
• Is the 3e (GL-BE6500) worth the update for WiFi 7 or is it overkill for my use-case? Maybe even a bad idea if it doesn’t support the official OpenWRT?
• Anything else I missed and should take into account?

In addition to the physical router recommendation, I have 2 more questions:

• from what I have read in other threads I believe I might need to keep my ISP’s router, or get another device to use as a modem before the router (I don’t know how to do that). Is that correct or can I just replace my ISP’s router with a router running OpenWRT (or similar) and be set?

• does anyone have any good resources to learn more about networks, modems, routers, etc.? for a newbie who is comfortable with the Linux command line but otherwise knows nothing about the topic.