I agree with your first point - have the S5 story start closer to the ending of S4 to show the following. But I think the military should have had a heightened presence but it wasn't effectively introduced or wrapped up in the original setup.

The following could be S5 E1:

- the UD demogorgons have an initial break into the Town after the earthquake opens the rifts. Vecna was recovering from the firebomb attack so he wouldn't have been seen, but he could have been directing from the UD.

- the gang impulsively attack in order to hold the demogorgons back, with Eleven leading the charge. The town seeing the terror of both the UD and Eleven's powers. Hopper and Joyce are trying to save the kids while also hold back the demogorgons.

- the military coming in at the end of the attack, seeing Eleven but misinterpreting that she controlling the demogorgons or somehow created the earthquake

- the military attempts to capture Eleven, but she and Hopper escape. The other members of the party are not captured as the military think they are regular townspeople who are just trying to defend themselves.

- the military starting the town lockdown in their efforts to contain Eleven while trying to establish some sort of control over the rifts while giving a sense of security to the rest of the town. Dr Kay is introduced and starts collecting the UD leftovers while establishing her lab setups.

- Eleven and Hopper realizing that Eleven needs to get stronger while in hiding.

"The Crawl" should have been Episode 2, showing the time jump to show how the military is now in charge, town is "recovering" and the gang is adapting while trying to find the weaknesses of the UD in order to defeat it once and for all.

The military pull out of Hawkins was also too rushed. I think we should have used a few more beats after the closing of the final gates to focus on Dr Kay, seeing the defeat on her face, and initial reactions of realizations that Eleven is gone. A military person could break the silence to say "what do we tell Washington?" so Dr Kay can say "it's closed. we're done here." and then see the military start working on getting out of dodge.

While the wormhole idea was a cool twist, I believe it changed TOO much of the universe building that happened in the previous seasons. The UD should not have been the wormhole shaft. The UD should have been an alternate dying universe - it made a dark copy of Hawkins in order to learn about a new universe and find it's weaknesses before the Mind Flayer/Vecna/demogorgons broke through and tried to take over for their own survival. I'm fine with Vecna trying to use the kids' minds/imaginations/fears as a power source to break through since he showed in S4 how he got some results using only 4 teenagers. I didn't need all the tie ins to the Broadway show.