Probably TrickyStore will not achieve its objective on the “stable” version of microG used in /e/OS. I think TrickyStore would only help move from device to strong integrity.
I think it is said that currently basic integrity would require a Google a/c registered as a minimum (and locked bootloader ??). The /e/OS build for Pixel 3a is not capable of relocking as delivered.
There will always be difficulties with some banking apps which rely on Google. Some clues in this thread [LIST] Banking Apps on /e/OS