The highest dose I've been allowed was 3 pumps oestrogel, like you say it only helps immediately after a dose increase then goes back to only a little better than naturally.
I tried half a dozen HRT combos before settling on tibolone, it's different, easier to use, but fairly unresearched.
Instead of an instant improvement that wears off pretty quickly, it starts unnoticeably and the benefits gradually build up. This is probably why the O&P type HRT is more popular. That gives patients an instant lift that they report back to their GPs and since that will be the last contact with the GP until something goes wrong again, it leaves the GP with the impression it's better than it is.
I get no unpleasant side effects after around 3 months on tibolone, initially I had abdominal pains, nothing else, but it makes me bleed once a month for five or six days, exactly like a period but I'm not to call them periods because I'm over 3 years post meno and that gets confusing for the so called experts
It has a built in antidepressant and anti-anxiety effects, far more than other HRTs. For me that is an important part of the purpose of HRT, but we are of course only allowed HRT for physical symptoms, not for how we feel, so it's often overlooked because the physical relief from crazy internal heat waves seems to be the only thing worth treating by the NHS and the relief from overheating is less from tibolone than from O+E type HRT.
We know testosterone helps the symptom of anxiety, it also causes miscarriage in women so doctor's reserve it for men. Even PM women are only allowed it for low libido!
Tibolone contains all three main hormones, not just O & P
The rules saying we are only to be treated for symptoms A, B & C, but not for symptoms D, E or F, would have been compiled without the advice of post meno women, so they are utter nonsense and I ignore them, listen to your own body instead.
Just thought I'd tell you my solution, since I build tolerance to oestrogen quickly, same as you do.