You never are. The original movie source 500-1000+ Mb/s looks amazing. The consumer available UHD 80-110 Mb/s source looks very good. The lossy 10-20 Mb/s streamed version only looks good when compared to older streamed formats.
HDR10, HDR10+, vs DV streamed is akin to arguing VHS vs S-VHS...I would say its even less than that. There is just too much information lost to really say "thats an amazing picture thanks to HDR".
Stream HDR content isn't "bad" its just no where near what your TV is capable of due to being limited by network bandwidth.
You said you have an LG OLED? If you have a media server or laptop capable of 4k 10bit output find a 4k HDR 10bit HEVC sample video like Jellyfish 100-200Mb/s or Samsung Travel 4k UHD. That still isn't the best your TV can do but the difference between that and HDR streamed content is night and day.