Upgrading the zone plan to Pro, Business or Enterprise will improve routing.
Argo Smart Routing improves routing. From my experience, it is as good as Enterprise routing. It does not require the Pro plan. In fact, if all you care about is routing, paying for the Pro plan is a waste of money if you already have Argo.
We recently conducted a test on our ISP, Reliance Jio, using their Fixed Line Broadband service.
Initially, we used the Free Plan with Argo smart routing enabled, hoping that it would provide smart routing. Unfortunately, after a few days of activation, we observed the opposite effect. Consequently, we decided to deactivate Argo smart routing. This is my personal experience: every new domain we add in Cloudflare performs exceptionally well for the first few hours or days, but then suddenly changes its routing policy (perhaps after reaching a certain bandwidth quota).
To address this issue, we upgraded to the pro plan, which resulted in a change of the routing policy to the Indian region within a few hours.
Upon analyzing the situation, it appears that Argo smart routing did not help with regional routing at all. It seems the final routing decision heavily depends on the selected plan. In the Free Plan, we were being served from MRS (France), after upgrading the plan it changed to AMD or NAG. That’s cool.