Interesting thoughts about London and its issues. I am a Brit who makes several social trips to London each year, and I don't think you have to worry too much about issues with the transport system - it's far from perfect, but I find it generally reliable, and there are ways of keeping the price down by doing your research on the TFL website and traveling off peak.
Back to the topic of the Courtyard, we started to use it as our London base post Covid, after our previous favourite (Marriott in West India Quay / Canary Wharf.) became so eye-wateringly expensive.
It is a nice, clean hotel, with great staff who treat Bonvoy members very well, it is also VERY competitively priced compared to other London hotels.
But, and it is a big but - the two downsides to it both involves its location. Firstly, it is a bit of a trek on the DLR from Central London, and then quite a walk from the station to the hotel - especially if you have luggage. Secondly, there is very little of interest in its immediate vicinity within walking distance (except maybe the Thames Barrier), no decent supermarkets and very few restaurants. I would think that for an extended stay, the amount of time on public transport and walking to the hotel would become a real bind.
For our (paid) stays recently, we have moved to the Stratford International, which is an Autograph hotel right next to the Stratford International station and a stones throw from the huge Westfield Mall / Olympic Park complex. I don't know how it stacks up for redemptions, but the cash rates are often pretty reasonable (for a London hotel). They also treat Bonvoy members well.
Nick