HRT doesn't postpone the menopause as such, it simply replaces the hormones the body is missing.
I am 62, had a premature meno which started in my mid 30s, so had hrt for nearly 25 years before stopping completely at 60. I tried a 3 year break in my early 50s but my flushes etc never subsided so u went back on hrt. I ended up with a Mirena with Oestrogel alongside and this was a good option at the time. When the Mirena ran out, I then tried Oestrogel with Utrogestan (supposed to be the best hrt regime for older women) and had awful problems with spotting, bleeding and cramps so decided hrt was more trouble than it was worth. I think my uterus simply didn't want to play ball any more.
It is now 2.5 years since stopping hrt (I still use local vaginal oestrogen for the urogenital atrophy and I will be using this for the rest of my life) - I have adjusted my life to cope the lack of sleep, loss of energy etc. I don't get as many flushes but I still can't control my body temperature so overheat very easily - summer heat is horrible. Some women like me are unlucky and things never truly settle but I am relieved to be free of the hassle of HRT.
Many women find the flushes settle quite quickly after they stop HRT especially when deep into post meno - you may just get a few months of problems and then things calm down. You won't be going through the fluctuations of peri meno and early post menopause that give problems for many years.
I wouldn't go to a higher dose as this could well cause even more bleeding. The Mirena would be you best alternative with Oestrogel alongside. DG x