An interesting question to be sure, and an inspiring vision for the future. However, I think at this is too wide of a question to generate a sufficient answer and a better start would be to read more in general about energy markets (pricing, how utilities decide pricing and assess expansion projects) and the general engineering concepts behind space solar power (SSP).
Some thoughts to generate conversation:
What is the design of the power satellite system? ie are there swarms of small ones or a few large ones
What is the power beaming design? You mention microwaves however I am under the impression that the best choice wavelengths for microwave beaming are very low density- this would massively change the ground system infrastructure design and thus impact cost.
I do not work with the grid so please take the following with a healthy dose of 'I should probably at least google this...':
Pricing varies between consumers, large scale customers (heavy industry, factories, etc) may be cheaper or actually more expensive depending on load usage than households.
Transmission costs would either be negligible or hugely impactful based on the ground system infrastructure (power beamed directly to user or one large plant)
Your description mentions "a world that is fuelled exclusively", this is very unlikely in almost any scenario unless the world is radically different than the world of today and more likely SSP would play a role in modifying current electrical generation.
At some point I'd imagine it all comes down to a massive estimates spread sheet where if the cost of total construction normalized over expected lifetime + cost of estimated maintenance < price per kwh in current grid market then BUILD. Some other factors play a role as in 'has this been done before?' and 'what do we estimate demand will be in the future?' but is mostly is down to cost (this mythical cost accounting spreadsheet has been corroborated by some discussions online I've had).
Potentially, however one must consider ones own values in this question. Personally I feel that the best case would be to resolve the conflict ASAP and to support this I would certainly accept the new Russian war (stated*) aims-that is the acquisition of Luhansk and Donetsk, if it brought hostilities to end. Also in my estimation it is entirely within reason that Ukrainian Leadership may (begrudgingly) accept this as well in a ceasefire negotiations. Thus any further damage to the Russian war effort would prolong this outcome.
Again I stress this is my own personal assessment of the situation at this specific moment in time and my modeling of the conflict so far has been very poor.
Also of note: any cyber attack action here would result in likely loss of life either by prolonging the conflict or more directly as higher probabilities of industrial/operational accidents. (I realise I have become paralysed)
This is something I thought about as well in the early days of the war however now I would question the utility of it in steering decision-making. At this point it seems unlikely that such actions could be framed as altruistic (ofc if you simply care more about Ukraine winning than ending the war this probably isn't valid), as this would be ineffective way of convincing Russian leadership to end the war while harming everyday Russians who have no control over the situation.