Toilets, Sinks, Showers, Tubs and Disposals - Stuck Basket Drain in Fiberglass Tub

I have an old fiberglass shower/tub (30+ years) which I'd like to refinish and replace the hardware on. The basket strainer appears to be stuck. I tried the method of sticking a pair of plier handles inside and turning them like a wrench using a pair of channel lock pliers but it didn't budge, and if anything it warped the metal crossbar slightly.

I've read some other posts which indicate using a reciprocating saw (or dremel) to cut through the strainer but I don't have either of those. Any other suggestions? If the pliers method didn't work, would a basket wrench have any chance? And if I need to use wd-40 or the like, how do i even get the wd-40 to coat the threads? I was thinking of using a box cutter or razor blade to slice underneath the lip of the strainer in order to squirt some wd-40 in that way, but was concerned about damaging the fiberglass.

Thanks for any suggestions.

I believe you may have better luck with the basket wrench (the one that looks like a tuning fork).