ifman13
Draytek actually has lots of documentation on their website, all step by step: https://www.draytek.com/support/knowledge-base/ (you might need to create a dummy account to access some articles). And their support is very good - I remember my router, purchased from eBay, develop a fault during peak of covid pandemic and they just replaced it within 1 day with no questions asked or silly excuses like it was purchased from eBay, its pandemic now and we are not working, etc, etc. As far as I am aware, they are the only company that are BT-certified to work with all UK ISPs and broadband types (BT is British Telecom, the largest ISP in the UK). They are mostly a business-to-business company and their products are very business-oriented, many UK companies use their equipment.
Not sure if its still the case, but they used to include a 500-page manual with their routers (and these are still available on: https://www.draytek.com/support/resources/routers#user)
The DrayOS might look confusing for a first-timer as it has lots of options and features, but its not hard to figure it out. Most importantly, the firmware and devices are rock solid and just work - never had any issue when a new firmware broke something, all is seamless with all the settings retained between updates (and its possible to fully backup/restore settings with no issues). So you don't need to worry about losing any settings when upgrading the firmware - its very straightforward and doesn't break anything. They provide firmware updates actively, I would say once every few months.
However, I don't think their devices are capable of delivering 900mbs Wireguard connections. My router, 2865ac, has just a 800mhz CPU so not sure if its enough (still waiting for my ISP to upgrade me to 500mbs full fibre to test). I would happily grab another Draytek router if there is one capable to deliver these speeds.