that's nonsense and I have no idea who started spreading this misinformation.
HDMI Forum VRR works perfectly fine at 1440p.
Rtings did VRR tests at 1440p with LG TVs where you can turn off FreeSync.
they plugged in an Xbox One S, set it to 1440p120hz and turned off FreeSync on the TV's settings to test if it supports HDMI Forum VRR and test the range of it.
this was before current gen was out so they were literally limited to 1440p when testing 120hz VRR on said LG TVs.
guess what happened? HDMI Forum VRR worked
at 1440p 120hz on an Xbox One S.
the TV didn't even support FreeSync when it came out initially, so their initial test was without FreeSync even being available.
BUT someone on here that owns an LG CX or newer with VRR support + an Xbox One X, One S, Series X or Series S could of course easily confirm this.
turn your console off, go onto your TV settings and turn off FreeSync but keep Gsync on (Gsync and HDMI VRR are combined into one setting on LG)
then turn on your console, set it to 1440p and see if VRR still works.
simple really. sadly my TV can not have HDMI VRR on independently from FreeSync as HDMI VRR support on my old ass TV is basically just a barely known extra feature on a single HDMI port.
the actual reason the PS5 doesn't support 1440p + VRR is because of their TVs. their TVs don't support it.
some from 1 or 2 years ago didn't even support 1440p whatsoever. others did support it but only on PC by forcing it through Nvidia control panel settings.
that's the real reason.
Sony refuses to support any standard that their TVs do not support. the PS4 Pro never got 1440p support because back then their TVs literally didn't support 1440p.
the PS5 didn't have it from the start because only now their TVs work with 1440p.
the PS5 also didn't have VRR from the start because their TVs still either lacked VRR completely or had massive issues with it due to being patched in after the fact.