Testing UDP vs TCD

Hi guys.

First of all, sorry if this is bad sub reddit, but figured here I will probably get some straight forward answer, since I saw here are more tech related people with this kinda stuff.

Issue is, I think that my ISP is throttling my TCP protocol (if I said this correctly) and it's about month old issue and so far I can tell it's EU based.

I noticed it basically by using (game) stream services like Shadow and GeForceNow. On Shadow, at least you get and option do you want UDP or TCP (always use UDP cause TCP base on it's nature can cause "lag")

Now with an issue. With TCP selected, I can only get ~15mbps and huuuge package loss, like 6-8% With UDP I get normal speed and some negligable P loss (<1%)

So, is anyone familiar with this issue? Or know how can I test my network with TPC vs UDP?

I would contact my ISP about this, but would know more before I rain fire on them.

So any help would be welcomed.