Don't unbraze it, there mostly a stamped in and out
label on the accumulator.

Well, in fact blowing through is only to clean the system.
But you still can have a restriction, even when you have a flow through the plates.
A capillary tube is a big restriction and you stll have flow.
You can see on the pictures I posted the restriction but there's still a flow possible.

Soldering schradervalves and measuring pressure gives much more reliable information.

Therefore, the temperature readings I mentioned are important measurements you have to take.

And pressure readings on the different sections are then the second most important readings.

These are not the easy jobs but you can prove now that you know your job.

I haven't re-read all the posts of this thread but where have you measured the suction pressure?
I ask you this because if you should have taken it somewhere on the low pressure side of the compressor body and not on the service valve itself, then you also can have a restriction in the mesh filter installed inside the service valve (or in the service valve itself)
But no, you have a hermetic compressor which has no mesh on the inlet but there's still the servicevalve. But it's good to know that this could have been also a possible restriction.

To look for a restriction in the accumulator: you need to solder a servicevalve at the entrance of it and compare this pressure against the pressure at the service valve on the compressor.