Yes, I know! I was saved back in the 70's, but only recently learned
about this fact.
this is only some of the article. it all won't fit here.

The Fourth Missionary Journey: What Happened to Paul after Acts?

The Good Book Blog

Talbot School of Theology at Biola University

UpdatedFebruary 24, 2023

https://www.biblestudytools.com/bible-study/topical-studies/the-fourth-missionary-journey-what-happened-to-paul-after-acts.html

By Kenneth Berding

“Paul’s fourth missionary journey? I thought he went on three
missionary journeys!” Yes, according to Acts, Paul embarked on three
missionary journeys. Then he was imprisoned in Palestine for a couple
years, transported under guard via ship to Rome (a journey that
included a shipwreck on Malta), and spent a couple more years under
house arrest in Rome. End of story? No. That is where the book of Acts
ends, but it is not the end of the story. There are enough biblical
and historical hints floating around to allow us to reconstruct some
of what happened next. As a result of such a reconstruction, perhaps
we ought to start talking about Paul’s fourth missionary journey.[1]

There are good reasons for every item included below. The order,
however, is somewhat uncertain. But I will place the events of Paul’s
fourth missionary journey in the sequence I find most plausible.

Paul appeared before Nero some time during his house arrest in Rome.
(God had promised Paul in a vision in Acts 27:24 that he would stand
before Caesar.)
Paul was released by Nero. (You see Paul expecting to be released in
Philemon 22, and perhaps in Philippians 1:19–26. The early church
historian Eusebius writing about AD 325 supported this with his claim
that Paul’s martyrdom was not during the period described in the book
of Acts, see H.E. 2.22.6).
Paul had planned to visit Philemon (Philemon 22). But since Colossae
was the opposite direction from Spain, and since we have some reason
to believe that Paul traveled to Spain right after Rome, my guess is
that Paul decided to forgo the visit to Philemon until after he
completed his mission to Spain.
   ........................
   So, yes, after Spain, Paul visited nine churches in Asia and Greece
before finally being arrested and being sent back to Rome to be
executed in Nero's persecution of the Church.
Lewis