Is there a way to upgrade RAM on 2017 MBP?

No, sorry. Not possible to upgrade RAM in that model.

However, it's unlikely the ram is causing the slowness, unless Safari is using a ton of RAM already or there is something else open using up RAM.

If you post an Etrecheck report someone may be able to see what is happening and offer some advice to fix or at least improve performance.

Link-> Using EtreCheck - Apple Community

You can also use Activity Monitor to see how your RAM is being used. If the graph is yellow or red it means there's a lot usage and 8GB is simply not enough for what you do.

If it shows green, then RAM is not the issue.

Link-> View memory usage in Activity Monitor on Mac - Apple Support

No, there is no way to upgrade RAM on your machine.

Lack of RAM is NOT the reason Safari is slow, 8GB is enough to run Safari at its maximum speed.

Have you looked at what Activity Monitor tells you about CPU, Memory and Disk usage?

That is a stupendously large amount of memory for Safari. Quit Safari and re-open your tabs one by one to see which one eats up so much memory by keeping an eye on memory usage. Nothing wrong with your computer.