I'm not quite sure from what you posted but is your main concern not being able to increase A time, or is it the night wakings?
If she is napping well on shorter than average A times, my usual advice would be to leave it be. There's no rush to increase A all other things being well. Yes many babies are on two naps at this age but many others aren't, so if shorter A times seem to suit better then go with it.
However........
A couple of things suggest to me that she may need a bit of a push. First the waking chatting 45 mins into her nap, and second the long happy NWs. Both of those are signs of under tiredness and I would say, signs the 3-2 transition has begun. My advice if she is sensitive to OT would be just to take things slowly. Increase her A time just 5-10 mins low-key activity for her first A of the day. If she manages a good nap, do the same with the second A. Hopefully that will take you to a little later in the day, so you can try for a shorter catnap of say 30 mins. Hold that new A time for 3-4 days before trying another tiny push. Really you are almost there anyway with 2h40-45 A time
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You will hit a point where there's no time for a 'proper' CN but it's too long to normal BT. If you get to that, opt for EBT instead, or a teeny CN.
So for example:
WU 6.15
Nap 9.15-11.15
Nap 2.15-3.45
Bit too long to a 7.15 bedtime......so either CN 5.45-6/6.05 (15-20 mins) - though it may be refused - and 7.15 BT or bring BT early to say 6.30/45pm. I'd favour EBT because that always worked better here, but others prefer to keep the CN if LO doesn't refuse it.
She may struggle initially to extend her A because of the disturbed nights. But hopefully a slow increase should improve the nights or give more settled naps, therefore making it easier to stretch that little bit further.