A chance to reflect on this particular trip now and... hmmm.
Part of the issue might be that the interiors were evaluated in daylight - once it's dark outside the lighting and mix of surfaces make for a very harsh environment in which to travel. Top that up with the ride quality, engine noise, 1/3 - 2/3 door opening, halting bilingual automated announcements and screens.
TfW needs funding to reallocate 197s from the long distance routes to increase capacity on the shorter runs for which they're designed, at which point they then need an alternative set of trains lined up that are suited to long distance travel.
The link below is a pdf from TfW with details of their current fleet, allowing a comparison between capabilities of class 158, 175 and 197 trains. Compared with a 158, the 197 cuts the number of seats per 2 car train by 16 and the number of loos by 50%.
Mark
https://tfw.wales/sites/default/files/2022-01/Fleet%20Access%20Specification_English_V1.pdf