If you are on an R3 PS Plus can still play your R1 games when they expire then you would be the first person to successfully get  the cross region PS Plus feature that all PS players have been waiting for ages.  Wait for the news from Sony when they release Uncharted 6 or 7.  Or God Of War 6 or 7.  If you're lucky. 

Games are not region locked but are subscription locked.  I you subscribed again next year or a few years later, they will be available to once play again.  I have many free games when I subscribed to R1 PS Plus.  But now that I'm Using R3 PS Plus, none of the games can be played.  Unless the same game was offer for free under R3 or I bought the game under my R3 ID then I can play the game again by reactivating it for R3.

Can always subscribe to both R1 and R3. R3 games this year not so bad. I stopped my R1 cos of the currency and had to use R3. But this year I feel that R3 is getting better. At least comparable to R1. We got GOW and Until Dead. Those are pretty good.