Selective combo of content from multiple fields

Greetings, all. Trying to use Format Values and regex scripting to modify an existing field using elements of content from another field, as follows:

%field1% = Box Set 5: Early Tracks (1965) [2024]

%field2% = Box Set V: 1965–1985 [Ficticious Records FR-3791/8524601423791-01/8524601423791]

Format Values / %field2%: $regexp(%field2%,^(Box Set V:) 1965–1985 (\'['.+?\']')'$',\1 $regexp(%field1%,^Box Set 5: (.+? \(\d{4}(?:–\d{4})\)) \'['2024\']$',\1))

Desired result: %field2% = Box Set V: Early Tracks (1965) [Ficticious Records FR-3791/8524601423791-01/8524601423791]

Actual result: %field2% = Box Set V: Box Set 5: Early Tracks (1965) [2024]

Is what I want to do possible, and if so, what am I doing wrong?

I have tried this:
$regexp('Box Set V: 1965–1985 [Ficticious Records FR-3791/8524601423791-01/8524601423791]',^(.*\:) \d+–\d+ (.+?)'$',$1 $regexp('Box Set 5: Early Tracks (1965) [2024]','^.*: (.*?) (\(\d{4}\)) \[\d+\]$',$1 $2) $2)
You will recognize the contents of FIELD1 and FIELD2
That expression leads to:
Box Set V: Early Tracks (1965) [Ficticious Records FR-3791/8524601423791-01/8524601423791]

Ok, thanks. I was still beating my head against a wall trying to figure out why my method didn’t work, but think I got it now. My original code was:

$regexp(%field2%,^(Box Set V:) 1965–1985 (\'['.+?\']')'$',\1 $regexp(%field1%,^Box Set 5: (.+? \(\d{4}(?:–\d{4})\)) \'['2024\']$',\1))

…but I failed to account for that extra part (?:–\d{4}), which may or may not need to be matched — some of my use cases have year ranges such as (1967–1968) — so it needed to be (?:–\d{4})?. Now it works.