Last year I had a problem after installing version 12.0.2, heard it was not supported and had to revert to an earlier version.
In the path setup it samples with 1.8 and I currently use 9.0.1
1.8 made the b4a (32 bit) process top out at 2GB using the optimized deer
With 9.0.1 the still 32 bit b4a process went to 3GB but the it still failed after 373 seconds (even though I had set its limit to 4GB)
It did do a lot of swapping during the process. The java code generation took 116 seconds.
Using android-28 (Can we use 29?)
All for b4a but I use same Java version for b4i.
Would a later javac make it go higher in memory and turn B4a optimized dexer into a 64bit process.
The installation instructions I can find on the site is for the minimum required, rather than the latest possible that will work.