I would solve it with these 3 steps:
1.) Convert Filename -> Tag with this Format string
%track% - %artist% - %title%
(this fills the year from the filename to your TITLE too!)
2.) Use Convert Tag -> Tag for the Field YEAR with this Format string:
$regexp(%TITLE%,(.*)\((\d{4})\)$,$2)
(This fills the 4-digit year inside brackets at the end of TITLE into a new YEAR field.)
3.) Use Convert Tag -> Tag for the Field TITLE with this Format string:
$regexp(%TITLE%,(.*)\((\d{4})\)$,$1)
$regexp(%TITLE%,(.*) \((\d{4})\)$,$1)
(This removes the space, the 4-digit year and the brackets at the end of TITLE)
It is nearly the same regular expression, just switch from $2 to $1 in the replace-part after the comma)
This would result in these 4 fields:
Please test it carefully.
And as always with regular expressions: They only works for the given specific use case!
Update 29.3.2026
To avoid a trailing space in the TITLE, please use the modified regular expression in step #3.
Thanks to @ohrenkino for the fix.