Hi Becky,
For us, UT tends to manifest itself with a silly o'clock (usually around 2/3am) put the world to rights chatathon and up to 30 minutes to fall asleep at BT.
OT usually results in EW/short nights (usually 10h), sometimes BT shenanigans, over emotional outbursts, falls Asleep easily but restless
I've not read through your whole thread but picking up the theme, with R I would definitely give a slightly earlier and longer nap a shot, especially when you've tried the other way and it's not working.
R's just gone through about 2weeks of needing longer naps (1h45/2h) but we're going to 1.5h again today given last nights chatathon
but I still think that maybe once/twice a week she'll still need a longer nap.maybe the same for you? I genuinely dont know but wonder if there needs to be a greater degree of flexibility at this age - still within a set routine as such but with some opportunity for longer / shorter naps
Hth and doesn't confuse things even more for you xx