We can not always avoid the use of "glue logic" - this is fine, as long it is limited to few tiny logic gates or so.

If we need more, then it would maybe already make sense to implement this "glue logic" in CPLD.

Wait CPLD's do not exist any more. They have been replaced with small FPGA's now!

Example, if we need:

1. two tinylogic gates
2. two signals converted from 1.8V logic to 3.3V logic

We can of course use still glue logic and level shifters, but we may already consider using Lattice machXO2-256 in QFN32 package.

So simple replacement of some small glue logic may get an FPGA into the game.

The benefit? We do not need to source the different components (the logic ic, the level shifter IC), we just take the one part we have in stock, the FPGA and implement that logic.