Misfire

Hello guys I’m new to this site , I’ve been having
issues with a truck 2005 4.6 V8 I just bought
possibly 2 month ago . So I realized the truck
starting shaking pretty bad and eventually check
engine light came up had it scanned. By advance to
see if they could let me know what codes it had .
And apparently was misfiring on cylinder 2 & 5. So I
figured might as well have plugs Changed s and
also went ahead change oil and oil filter, changing
the plugs were bad , some had bad grime build up
that socket wouldn’t sit correctly onplugs to extract
, eventually after using air hose and spray to try and
be able to clean out a bit helped take them out . I
figured this was definitely the problem and
expected possibly rough start at beginning if any
grime went in cylinder , and yes issue continued for
quite a while ran it abt 50-60 miles and still same
issue shaking , so then I replaced the coil boots cuz
some did seem cracked , ohh and brand new spark
plug just placed in on cylinder two , was black
seems was not burning , we played with coils to
make sure none were bad and noticed that pulling 2
or 5 coil white engine running it didn’t make the
shaking worse , we changed spark plugs and coils
to different cylinder and issue didn’t follow them
same cylinder was the issue . We gave up and just
took it to shop to see if they could figure it out and
now apparently cylinder 2 has no compression ,
and whole engine is a bit low on compression
throughout all cylinders, I was told I would need
new engine and man I just bought this truck 2
months ago and was not wanting to spend 3800
they quoted me for new engine ? So my question is
would I need new engine or could it be something
else I’ve been reading threads couldn’t find a
conclusive answer , can compression loss be
caused by anything else , a vacuum leak or intake ?
Head ? gasket , I’m really not looking forward to
spending that much for new engine and labor but if
I have to I guess I will , but I wanna make sure that’s
the only way to fix ? Or if anyone has any other
experience with this and found out what issue was
? Any wisdom would be greatly appreciated