Should not be a problem at all.
Wonder if someone Red-Loctited it in? Wonder if someone made a Guide Rod for it that does not fit well?
With the Slide Assembly removed from the Frame, place the Slide Assembly bottom side up, on a flat non-marring surface, such as a Work Mat.
Hold onto the rear of the Slide with one hand, and with the other, press the rear of the Guide Ros slightly, lift up slightly and to the Rear and the Guide Rod and Spring should EASILY come out.
IF that does not work, then soak the Slide Assembly in Kerosene or some other penetrating solvent that won't harm the Finish, for about a Week.
I have both Full Size and Compact Series 88 BTA90's, and they've been Great Pistols!
Compact Series 88 BTA90
See Video Link below:
https://youtu.be/iLdDMexpxv0?si=hiz4SiXRAaq8Bn-c