Dimensity 9400 is spectacular. the 9300 was very good too, but the new 9400 is amazing. It fully matches Snapdragon 8 Elite (Gen 4)
It even beats it narrowly on battery, which used to be the strongest point of Snapdragon over Dimensity.

https://nanoreview.net/en/soc-compare/qualcomm-snapdragon-8-gen-4-vs-mediatek-dimensity-9400

but what the hell will be in my next flagship phone I’m planning to buy next summer

Probably a Snapdragon X Elite Extreme Ultra Mega Pro XxxxX or whatever their naming scheme is now.

The odds that ARM will get an injunction preventing Qualcomm from selling chips is basically zero. The courts are rarely going to torpedo an entire company over a dispute like this when the facts are very much in dispute and very... subjective.

This is a scenario where nothing changes until the case ends and then either ARM has to build another moneybin to store their settlement, or literally nothing happens.

Google's fine. They're using ARM cores that are built on Samsung's shittier manufacturing process. Next year they're going TSMC which should improve power consumption dramatically. The lauded Dimensity 4000 also uses ARM cores, just newer and built on TSMC's process. By the same token, newer Google SoCs should experience similar performance as they update the cores and manufacturing.

MediaTek 9400 fits within 10% of Snapdragon 8 Elite, so if you don't intend to load a custom ROM, I'd say there are options.