I've done new flooring, and in some cases (to get to the flooring under the edge of the slide) the most effective way may seem a bit extreme to you . . . You can remove the slide.
>IF< you want to venture down this road . . . Your slide is supported by the two arms underneath it. You can unbolt the ends and remove the slide completely.
There is usually one electrical cable connecting the 12V lights in the slide to power. Located at one of the arms.
The slide requires support (obviously) under the slide once extended (like two saw horses, etc). It is a good idea to mark the position of the hardware on the end of the arms holding the slide to ensure they bolt back up in the same (adjustment) position. A mist of white spray paint works well.
Alternately (in lieu of removing the slide) you can remove carpet, etc. off the front edge of the slide, maybe get a little better access, but typically the floor of the slide will still be in your way. The slide can be jacked up on the inside end of the slide once fully extended. Two floor jacks and 2x4's on the outside edge work well. Of course it will only go as high as the (small) gap at the top of the slide. That's maybe an extra inch of access, may or may not help much.
On the positive side, any irregularities of installation UNDER the slide won't be seen, so it does not need to necessarily be perfect. I hope this helps a little(?).
Rich, MCPO, USN, Ret.
RV Service Tech
RAM pulling 2021 GS TT