We are all ideological, its just we might not subscribe to a particular set ideology as you yourself state. There are true Ideological believers of course, but they tend to be around fringe beliefs like Nazism, White nationalism, Anarcho-syndicalists and the likes. The vast majority live around the centre with various leanings both leftwards and rightwards.
As for the left and Unionism, there are different thoughts. Blair for instance thought he could save the Union by introducing devolution and to some degree he did, until Brexit came along. Again it goes back to the constitutional settlement though, Scotland quite fairly in my opinion resents rule from London and the UK is one of, if not the most centralised states in the Western world. A lot of people on the left also supported Sinn Fein (not the IRA) because Irish unity was a goal and Sinn Fein were a Leftist party. As you say its about local democracy. I think the City mayors have been a success, in Manchester we have control over part of the Cities health budget that means we can meet the needs of the people of Manchester which maybe different to the needs of the people of Dorchester. I support local democracy, the Conservatives however centralise power.
Its a good question though, i do think post COVID, there has to be a new Constitutional settlement, there has to be an overhaul of our democracy as too many voices are not heard and too few voices are heard too much. I would probably support PR and an elected 2nd chamber, a system of regional assemblies and more metro mayors with increased powers. That is just because the needs of different areas of the nation vary so much. We also need a new system of local investment banks that can drive regional growth. After brexit and post Covid the country has to change because our current system is outdated and if the union is to be saved, it has to be done soon. Otherwise Scotland will be off, Wales will maybe follow, Irish unity is possible and we are left with a rump English state dominated by London and the SE