I'm stressing a bit about the advice about not creating bad habits...
Honestly? By 7 months old it's too late to be worried about that. If you wanted "good" habits (ie sustainable) then they needed to be in place by now. If they aren't then I honestly would day forget worrying and just focus on surviving best you can and making life as easy as possible without stressing and worrying about it.
There is no magic answer here.
It sounds to me that by being so insistence on independant sleeping and avoiding Rods For Your Own Back, you've ended up making sleep so hard for baby that it's ended up being the cause of The Rod.
Dummy for example. Quick, simple, easy way to help baby get back to sleep with no fuss. But they "don't keep him asleep" you say. They aren't meant to. But what they do is teach babies to link one sleep cycle to the next - buy offering way and to resettle easily before baby actually wakes properly.
Co-sleeping or room sharing (cot next to your bed) is another example why not rushing for independant sleeping can lead to quicker independant sleeping. Being right there to resettle immediately, ideally before you or baby properly wake, teaches baby to link sleep cycles so get better at sleeping for longer. It also gets you much more sleep.
With baby next to you (in sidecar cot or cosleeping) and a dummy, a wake up goes like this: first murmur from baby, reach arm across, locate dummy, reinsert dummy, everyone back to sleep. All done without even opening your eyes or moving from under your duvet. Over time baby learns to link sleep cycles so doesn't wake, so doesn't need dummy reinserts and doesn't need you there in the night.
Compare to the 7 month old with a mum too worried about Rods For Her Back that has baby in own cot, in own room, with no comfort source and hopes they sleep.
But babies need comfort of some form (independant or parental) to sleep. By giving no independant sources of comfort (dummy?), parental comfort is required. So at every wake up baby wakes, cries, wakes properly, parent gets up, walks to another room, rocks/cuddles/feeds back to sleep or just listens to baby cry. Then does it all again a few hours later.