Embrace limits.
There's a limited energy budget at Earth's surface.
Humans have benefitted by ransacking a treasure store of energy which accumulated over 100--300 million years, and will quiet possibly not be recharged in the remaining span of habitable life on Earth (about another 800 million -- 1 billion years). Even absent energy concerns, we've also been ransacking rich mineral deposits some dating to the earliest eras of life on the planet (banded iron formations, the result of blue-green algae growing 3 billion years ago). Absent ore-formation through minerological and biological processes which concentrate minerals to levels which make further extractuion and purification viable, we'd be stuck with far fewer choices for materials.
The largest challenges in degrowth are not technological but political, cultural, economic, fiscal, and ultimately about shared beliefs, values, and vision.
Over nearly 50 years of awareness of, reading on, and researching this problem, that's become abundantly clear, and hopes of a successful negotiation of this particular transition are not high.
The energy landscape is largely known and has been for the past 70-150 years. Solar, wind, hydroelectric, geothermal, and biomass.
We're already making use of much or all the available biomass (as food, with considerable fossil inputs), hydro, and goethermal resources. Solar can be ramped up, as can wind. Both produce power of a different scope, cost, and quality (availability, variability) than what advanced technological countries have come to rely on.
Nuclear is an option but faces its own issues: limite fuel (uranium and plutonium, possibly not so much in the case of thorium), major political and social-organisation risks, and of course a very long-tail disposal risk extending beyond the span not only of all our social institutions but of civilisation itself --- tens of thousands of years.
William Ophuls and Thomas Homer-Dixon are two authors in particular who have been looking at the political challenges of adapting to ecological limits.
I strongly recommend all Ophuls' work, though Ecology and the Politics of Scarcity (first published in 1977, revised ~1994) and Plato’s Revenge (2011) are probably the best starting points. The first secion of Ecology in particular makes one of the most cogent arguments for the Limits to Growth premise I’ve found anywhere.
At Worldcat:
https://www.worldcat.org/title/ecology-and-the-politics-of-s...
https://www.worldcat.org/title/ecology-and-the-politics-of-s...
https://www.worldcat.org/title/platos-revenge-politics-in-th...
Also available via Archive Org:
https://archive.org/search.php?query=william ophuls
Ophuls has a website with more recent writings, though the essays are missing from the present-online version:
https://web.archive.org/web/20190311104851/https://ophuls.or...
Thomas Homer-Dixon is referenced by Ophuls several times and seems closest in spirit to his work:
https://homerdixon.com/