I used to update my Fenix 3 by downloading BIN files from Garmin website and just dropping it onto the watch’s filesystem.

From EPO I used https://github.com/scrapper/postrunner

First you need to define your requirements.

1. Is just for browsing and the router will be connected to a VDSL link with something like 100/250mbit?
2. Are you planning to have a server at home and transfer a lot of data within your LAN and need a lot of throughput?

If it’s 1, then you can get a bunch of used ac routers, something like Archer C5 or C7, flash OpenWRT on it and configure 802.11r within your LAN. This requires some fiddling, but you don’t need to spend a lot of money on a decent mesh.

For 2, well you with with €200 budget it’s going to be trikcy.

MacBook replacement is difficult even when you don’t limit yourself at all. I doubt you will find something with a build quality, display, battery life and thermals, in EU, that would come close to Macbooks. Therefore set you expectations right.

I’d add XMG to the brands mentioned here.