This is really quite a dilemma for you and one only you know the answer since I can only look from the outside.
However, one sentence that jumped at me is "Every time I see my therapist she feels like a stranger again." and this is a really important and extremely well researched developmental phase and I highly recommend you come to acquainted with at least rationally and logically if you have not already. I feel perhaps this is the main reason your therapist is increasing the sessions to get through that phase safely and with her watch. it is one of the most challenging phase for any of us growing up and when it is interfered with trauma - just forget about it. One can only reprocess with another - often with therapist.
All that being said, I was one of those people that spent once a week for couple years. Every other week for over a year. and now I am back to twice a week. In all of these, I was in the same group therapy (people change but same group leader etc for the 4yrs) and not my therapist and at the top I had other short term group therapies early on my treatment. I needed that much support to just get by after I opened the gate of trauma.
My opinion is this:
Dealing with childhood trauma or cptsd - once a week (IMHO) at the beginning of therapy is not good. It is easy to get destabilize and flooded (especially the first time therapy). One needs a lot of support imho. but there are many people who have great support intrinsically who can also do this so perhaps that was you. you could do that. and that is great strength to have.
Every other week - again imho, good for after many years of therapy and sort of maintenance but not again dealing with cptsd and when one is symptomatic. I find by the time I got back to therapy so much happened both inside and outside and it was just dragging...I felt wasting my time and also more frustrated so why pay for this. it was not working for me but again it may work for those that have different experience or strength.
Twice/thrice and more times in the week - again just my opinion and experience - it does work better, things are dealt with much shorter and defenses or symptoms do not become too crystallized but the goal at least for me is this: this cannot go on forever ...no one has this kind of time to stay state of uncovering and opening wounds and still just act normal after each session UNLESS one really needs because one is really unwell or unstable and truly needs this. So I set a mental goal to try this for 2 years or less (having Zoom during pandemic made it that much easier) - no travel time so perfect for now!.
Because you and the therapist and you came to this conclusion and you have valid reasons to consider the time, travel, the money, and pain that is involved, I wonder if you could do some of them on the phone or Zoom or something like to lessened the hours involved and take them as touch base days. Something to think about. I think you can do it as you have shown for five years with this therapist from what you posted but also only you know how much time and energy you need.