From "quarantine and chill" to victory kisses -- Miami Heat star Tyler Herro and GF Katya Elise Henry are going strong in the NBA bubble ... celebrating his huge win with some smooches on the court!!

It's been one helluva pandemic for the 20-year-old baller -- remember, the dude pulled up from DEEP and started flirting with the model on social media back in March.

Things got serious in no time ... and now they're one of the hottest young couples in sports.