DEN-PRG and VIE using Cap One Miles

I'm making this post mostly because I may be overthinking things. I'm planning a trip for summer of 2027 from DEN to VIE and PRG (flying into one city and out the other, I don't really care which) for 2 people in J. Ideally, I would like to avoid repositioning flights, which I've had to do in the past.

Flying Blue availability has been very tricky to find out of DEN for the past year or so. Assuming I don't get lucky with Flying Blue, that basically leaves me with two options - British Airways or a Star Alliance carrier. If I were to book BA, it would probably make sense to take advantage of the current transfer bonus to JAL. If I do open-jaw booking with JAL, it would require about 205k pts, plus $2,040 in fees for both of us (I would also need to spend some more money on seat assignments to sit together because I have no status with BA). I'm tempted to go that route because JAL seems to get access to BA seats consistently at the end of the calendar (around 355 days). However, I would be transferring somewhat speculatively (about 3-4 months before booking the tickets). Alternatively, I could try to find star alliance availability, which would cost a bit more in points, but the fees would be drastically lower. The downside there is that the availability seems to be released much later (assuming I book them using Aeroplan or Lifemiles). The past year or so there has been pretty open availability on the Lufthansa A380 out of DEN, but they are cutting back on that flight for this year.

Am I overthinking things/being too picky in looking at the fees for BA as being too high? I could also hedge and go with BA for one leg, and star alliance for the other. For some reason, the fees are somewhat proportionally lower when booking one-way with JAL (seems to be about $450 outgoing and $400 inbound, per person).

What would you all do? Would you take advantage of the transfer bonus to JAL? Or just wait and hope for Star Alliance availability?