You're already doing pretty well considering you've been playing for 5 months.
You shouldn't have to many problems with 200BPM streams if you can do anything else 200BPM pretty well, unless you're not that used to streaming (which you probably aren't)
I'm around your level. Highest I can stream for a short time is 240BPM, but that's like 15~ notes or so. My first steps were like 145BPM streams, but I learned 175BPM before 140-160BPM.
I think the most important thing is to not just focus on streaming itself, but just playing regular 200BPM+ maps that also feature streams so you can also get used to that kind of tapping speed. All that streams are after all is twice the speed of the "singletaps" in maps, so if you learn how to singletap them, you should be able to stream them soon enough since all you have to do is singletap x-BPM with 2 fingers instead of one. The tempo for each finger remains the same.
Anyway, the maps I played and still play a lot and imo helped me improve streaming and tapping overall:
https://osu.ppy.sh/s/339708 | 170 BPM, like 90% streams
https://osu.ppy.sh/s/173422 | 172 BPM. Bursts and some streams. 4-5* are all good practice.
https://osu.ppy.sh/b/173391&m=1 | 174 BPM. A bit technical streams. (I didn't play this until recently)
https://osu.ppy.sh/s/184301 | 174 BPM. Bursts / Streams. Really fun.
https://osu.ppy.sh/s/104260 | 175 BPM. Long streams. LC / Insane are both good practice
https://osu.ppy.sh/s/128931 | 175 BPM. Pretty much 100% Streams.
https://osu.ppy.sh/s/277279 | 175 BPM. Good tapping practice overall.
https://osu.ppy.sh/b/53554&m=1 | 178 BPM. Not necessarily a lot of streams but I think it trains tapping tremendously.
https://osu.ppy.sh/b/785982&m=0 | 180 BPM. Classic and good tapping practice.
https://osu.ppy.sh/s/53923 | 180 BPM. Bursts and tapping.
https://osu.ppy.sh/b/83338&m=1 | 184 BPM. AR8 Streams (I didn't play this until recently though)
https://osu.ppy.sh/s/47754 | 190 BPM. Streams / triples / fun map overall. Lunatic diff.
https://osu.ppy.sh/b/807070&m=0 | 190 BPM.
https://osu.ppy.sh/s/153776 | 190 BPM. Lots of bursts. It also goes NYAO and NYA a lot. Impossible to tilt off this map
https://osu.ppy.sh/s/132398 | 190 BPM. A bit technical. Streams / Bursts.
https://osu.ppy.sh/s/22276 | 192 BPM. Contains pretty much everything. Imo one of if not best map in this game.
https://osu.ppy.sh/s/48979 | 195 BPM Contains some simple streams and is a great map overall (have hitsounds active)
https://osu.ppy.sh/s/93523 | (HT) 195 BPM. Really fun and good streaming practice. Isn't actually that difficult to play on HT.
https://osu.ppy.sh/s/72740 | 200 BPM. Probably the perfect map to practice for you
https://osu.ppy.sh/s/382400 | 200 BPM. Mostly streams but 6*
https://osu.ppy.sh/s/20949 | 200 BPM. Both diffs
https://osu.ppy.sh/s/114392 | 200 BPM.
https://osu.ppy.sh/s/32046 | 200 BPM.
https://osu.ppy.sh/b/110347&m=1 | 210 BPM. Bursts and singletaps but also trains fingercontrol.
https://osu.ppy.sh/s/185927 | 215 BPM. Is also 6* but if you can manage yourself on it it's good practice for 1/6 and normal streams.
https://osu.ppy.sh/s/90385 | 224 BPM. Bursts and Streams.
https://osu.ppy.sh/s/86009 | 230 BPM. Play the 4*
https://osu.ppy.sh/s/28705 | 240 BPM. 4* is best singletap practice, 5* is a good balance between singletaps and short streams / bursts.
https://osu.ppy.sh/b/304179&m=0 | 240 BPM. Singletaps and some bursts / stacks. Prob one of the most fun 240BPM maps.
https://osu.ppy.sh/b/973607&m=0 | 248 BPM singletaps. Play hyper diff
https://osu.ppy.sh/b/655684&m=0 | 250 BPM. 4-5* are all good practice.
And for the small chance you don't hate old maps:
https://osu.ppy.sh/b/31819&m=0 | 170 BPM Streams and tapping, good stamina practice (like a lot of DJpop maps imo)
https://osu.ppy.sh/s/5445 | 180 BPM Tapping
https://osu.ppy.sh/b/58063&m=0 | 180BPM, Tapping
https://osu.ppy.sh/s/5807 | 200 BPM, features 1/6 streams IIRC
Not mentioning the obvious Stream practice maps because those are really easy to find by yourself if you wish.
Generally you just have to "play more". To me "Kokou no Sousei" 4* seemed impossible because I couldn't grasp the singletaps in that map. Same goes for those 3-4 little parts in "Everything will Freeze" until eventually I just tryharded and kept playing high BPM stuff and was able to singletap it.
TL;DR
Play more medium/high BPM maps. Not just 100% stream maps. You want to learn 170-250BPM everything, not just streams / triples. Just keep at it and don't get discouraged or fall into the trap / mindblock of thinking you "just can't" tap / read that fast.
If I can do it, so can you.