There is still minimal evidence that third parties will arm Ukraine sufficiently for it to indefinitely prevent Russia from slowly advancing, let alone recover lost territory. NATO could admit Ukraine in the middle of a war and take up the war, but that is absurdly unlikely - there is less evidence of a will to intervene than of a will to adequately arm and supply. There is a secondary course by which NATO instead draws a line and offers Putin the choice of not crossing it to avoid an escalated war with NATO. NATO could admit Ukraine after some resolution of this current phase, which would also amount to a line-drawing ultimatum to Russia. Admission could be complicated, if any NATO member plays politics with the proposed admission.
Without a strong and determined alliance backing it - NATO or some other willing coalition - Ukraine will lose in chunks if Russia really does want more of it. If some kind of peace now is a prerequisite for NATO admission - to avoid the complication of drawing NATO into an active war - it's another reason to make some kind of peace.
The choices for everyone doing a little but not enough to help Ukraine remain:
Escalate and win.
End it to cut losses, arm and re-arm, rebuild infrastructure, and prepare.
Stay in just enough to drag it out and lose.
Pick the first or second, but for fuck's sake desist with the third.