Clearly, a lot will depend on what happens with Covid-19, Brexit and life in 2023/24.
Additionally, the Tories have a habit of occasionally going left field and not necessarily electing the obvious. You would think Sunak is the obvious man, but the party is as split now as it was under May and Cameron. Plenty of time for Sunak to upset his party and his supporters with whatever he does on clawing money back from us in taxation in the meantime.
I hope Starmer edges it with a workable majority, long way to go. Labour and the left need to get behind him and not cause waves and let him forensically pick apart the Government lies and deceit. Parliament has lost control at present which works in Johnson/Governments favour. I do think some of the more reasonable in the Tory party are recognising this and are wrestling Ministers from the back benches. At present we have a mini dictatorship rather than parliamentary control and sovereignty.