Step by step process for setting up L2TP connection (not inc IPSEC)?

I have a GL-AR300M-Ext which is working great with OpenVPN but the speed just isn’t sufficient with OpenVPN connection (wired not wireless). For the use I’m thinking of I don’t need strong encryption (or really any encryption to be honest) so I’d like to set this up with an L2TP connection. I had a spare very cheap basic TP-Link router that I setup a L2TP connection on and everything is fine with it but I’d rather use a much smaller travel sized router for this job, GL-AR300M-Ext would be ideal which is why I bought it in the first place.

Looking in the interface there isn’t an easy setup option for anything other than OpenVPN though, does anyone have/could put together a quick step by step process for setting up L2TP connection on one of these? I see it can’t do L2TP inc IPSEC apparently but as I said, IPSEC or other encryption not needed so should be possible.

Is there a package to download that would add this option to the initial blue settings menus without having to trawl through all the advanced settings screens? The easier the better really as I might switch between OpenVPN and L2TP on occasion so the fewer steps the better.

I suspect this is really easy and involves few steps (certainly was on the TP-Link router) but don’t want to go messing around with things I’m unsure about and just causing problems, always easier to set something up properly than have to undo a mess first!

I’m sure there must be other who would also like to see this as an easy to follow guide.

PS WireGuard would have been a nice speedy alternative but none of my VPN providers have this yet and I’m not looking to sign up for another VPN, L2TP will be fine for me.

Ps I’m on 2.27 firmware