Press fits don't work well with PTFE. It cold flows (crereeps) under pressure so does not make a good mechanical joint.
The best way I came up with was to turn a series of shallow grooves in the PTFE and then cut a few grooves length wise connecting these grooves. I think I did 0.02 wide grooves spaced about 0.05 apart and about 0.005 or 0.010 deep. This was years ago on some bushings.
I roughed up the inside of the hole and then used epoxy to hold in place. The epoxy does not stick to the PTFE but flows into the gooves and makes a mechanical joint. The circular grooves keeps it from pushing out and the length wise grooves keeps it from turning so you can machine it if necessary.
Gail in NM