Like SR-71, J-36 will have significant IR signal when super-cruising. It should be easily detected by optical satellite. With Starlink Network only cost $20B~30B, about the lifespan cost of a CVN. If USAF launch a optical satellite network at the scale of Starlink. Is it still meaningful to develop stealth plane?
Once a J-36 has reached its patrol area, it presumably would reduce fuel consumption to a minimum. So it would be at subsonic speeds which also means maximum cooling capacity for the electronics and radars.
---
On the second point, if space-based satellites can provide a weapons grade targeting solution and also mid-course guidance for missiles.
Presumably China can launch its own satellite constellations.
In that scenario, what matters is the speed of aircraft and the range of missiles. Along with how many aircraft and missiles are available.
On these measures, China has a large advantage in the Western Pacific, mainly due to geography.
---
It also means that the B-21 is toast because:
1. Its stealth doesn't work
2. it doesn't have the speed to outrun a missile, nor the agility to dodge a missile
3. It can't go supersonic and give its own air-to-air missiles a boost in terms of range
Note that China hasn't committed to the H-20 yet, so China will have saved itself tens of billions.
---
So in summary, the US loses even more if space based targeting becomes a reality in the future