Unfortunately you have likely just missed the best time to buy a new TV with the 2019 models just being Introduced now. If you head I to a store however you might get lucky and they might still have some 2018 TVs sitting around. I work in TV sales and I know you said you want to go with Samsung, firstly Samsung do not sell OLED TVs, this is likely due to the fact that lg makes all OLED panels for the TVs and both companies are Korean and are rivals so Samsung likely refuses to buy them.
So then, OLED or QLED. The question everyone always asks, truth is though that there is no competition. OLED is undeniably better in nearly every way apart from brightness, the nature of OLED gives it low input lag, better black levels and awesome colours, they typically arnt as bright as Samsung TVs, but Samsung fake their brightness results and they are taking about peak brightness which they are able to reach for literally a few seconds when a test pattern is displayed.
Next thing to note is that most TV companies also make QLED Tvs just with different names. QLED is all branding, it’s what Samsung is best at and it’s why everyone thinks they are the best. In reality they just have very clever marketing. Look out for Sony’s trilluminous TV, LGs Nano cell as these are both the same technology as QLED but are usually better and cheaper.
with that out the way the next thing to consider is OLED burn in. Don’t worry, this is not as big of a deal as everyone makes it out to be. Since you seem to be a retro gamer judging by the fact you have an OSSC, it’s very very unlikely that you would ever experience burn in unless there is one game that you okay literally all the time for hours on end then it’s possible that the life bars and stuff like that could possibly burn in, vey unlikely though. If you use scan lines maybe switch them from top to bottom every now and then just to be in the safe side.
Samsung TVs are overpriced and there are much better options out there for retro gaming. The Sony X90f for a non OLED tv and literally any OLED will give you the same picture quality since you will be turning the TV to game mode which disables most of the processing and all OLED panels come from LG and are the same as I mentioned previously.
Hope this has given you some idea of what is a good TV to go for. Any other questions let me know, as I say I work with this stuff so I know what is bs and what is not.