This ones a loose fit for your question but I think it is close enough for consideration.
Have you considered "Into the Looking Glass" by John Ringo?
Gates are opened between Earth and other worlds, and aliens start swarming through several of them.
The first point falls through as it is very near future and the main character is a heroic physicist,...
Googling for "Eliza Tertia" indicates that this is The Forever Formula (1980), by Frank Bonham.*
Per this review:
The veteran author of nearly two score novels, Bonham has his ups and downs. Here he treats a theme of cosmic significance and potential richness with the superficiality and careless logic of a 1940s movie serial, complete with endless ...
The Forever Formula by Philip E High
After sleeping for 180 years, Evan Clark awakens to a world populated
by old people kept alive by drugs, eludes those who want his formula
for eternal youth, and joins the Juvie Underground
Sounds a lot like the 1961 german novel Der Orchideenkäfig by author Herbert W. Franke, seems to have been published in English as well in 1973 as The Orchid Cage.
The plot goes like this:
A degenerate humankind lies most of the time in high tech fully automated beds and plays games. Those games are not VR but involve real robot-avatars. These avatars come ...
This might be the Gone series.
One minute the teacher was talking about the Civil War. And the next minute he was gone.
He just vanished - along with everyone else over the age of 14 in a 20-mile radius around Perdido Beach, California, which is also now enclosed by an opaque, impenetrable dome. The children left behind find themselves battling hunger, fear,...