Comment by TacticalCoder

It's a bit tricky in that browsers may be using TCP_NODELAY anyway or use QUIC (UDP) and whatnots BUT, in doubt, I've got a wrapper script around my browsers launcher script that does LD_PRELOAD with TCP_NODELAY correctly configured.

Dunno if it helps but it helps me feel better.

What speeds up browsing the most though IMO is running your own DNS resolver, null routing a big part of the Internet, firewalling off entire countries (no really I don't need anything from North Korea, China or Russia for example), and then on top of that running dnsmasq locally.

I run the unbound DNS (on a little Pi so it's on 24/7) with gigantic killfiles, then I use 1.1.1.3 on top of that (CloudFlare's DNS that filters out known porn and known malware: yes, it's CloudFlare and, yes, I own shares of NET).

Some sites complain I use an "ad blocker" but it's really just null routing a big chunk of the interwebz.

That and LD_PRELOAD a lib with TCP_NODELAY: life is fast and good. Very low latency.