Lightroom Classic can't find my cr2 files?

Might the "other photo programs that you use" have modified these Raw files in any way? You could try with a freshly-taken or downloaded sample Raw, which has not undergone any action by other software.

Also you could copy one of these Raws into a separate location, ensuring that any sidecar files are not included in that copy.

More fundamentally, it may be that all of the Raw files you are looking for, are in fact already imported - and hence, do not appear as importable (for example, if your Import screen was filtered to show "new" files only, you would not see these at all). AND if your view filter in LR was such as to conceal the Raw file type systematically, it could appear as if there were none present. This would be made apparent, so far as already imported photos, by setting view filters to "None" in the Library filter bar and then starting out again from the "All Photographs" view in Catalog panel.

Regardless, a completely fresh Raw image of a supported model, should still show up as importable in the Import window.

Two perhaps OT questions which are however, I believe, related:

Why don't you work to get your LR up to date? Why don't you use the PS to which you are entitled.

You are paying a significant amount of money every month for the right to the latest versions of those apps. For the last 9 months you have received no return on your money other than the pleasure (?) of a lower bank balance.

Your subscription is valid and paid up, isn't it?

And a long shot, In LR click on Help, click on System Information. double check you are in fact running LR 7.5 and not some very old other copy still on the PC (don’t laugh, it has happened)

Incidentally, do you have the same issue in PS?

Lightroom can not view them, when?

At import?

At import via memory card?

At import via camera thru USB?

At import via hard drive? If you copy them to the PC outside if LR, can LR import them?

After import?