You can get to 25-30# total loaded with food and 2L of H20 for pretty cheap.
(at least its a lot better than 45#)
You should eventually shoot for a 5-6# or lighter big 4.
12# or lighter base is a good number.
That said if you like tents a decent and fairly cheap setup would be ...
Campmor 20dF bag for - 36 oz
Spitfire tent with new stakes - 46oz
Thermarest pro 3 short - 11 oz
GG Miraposa plus with the internal frame - 24oz
7.5# total for about $400
Add 6# for everything else, 4# for 2L h20, 10# of food for 5 days for a total of 27.5#. 17# lighter.
If you spend $120 more on a tent, like a moment your big 4 would weigh 6#
If you spend substantially more on everything...
MB #2 SS UL bag, gatewood cape, bug tent, regular neoair, GG Miraposa your big 4 would weigh 5.4# but your rain gear is covered too with the gatewood cape which saves another pound.
Trade out the MB #2 for a ultra 20 quilt and your big four is right at 5#.
Over time reduce all your other gear to 6# or less.
This will take some work and some more $. Clothing is a lot of that and just cutting misc crap you dont need than anything. Again 4# for 2L h20, 10# of food for 5 days for a total of 26#.
Food and water are so heavy you sort of hit diminishing returns as you go lighter and lighter but if you can skimp by on 24oz of food a day and gorge at a resupply then it gets lighter still at 22.5 fully loaded.
Some People go even lighter still, like 5# base etc which is really lean and very specialized with a lot of cuben.
Too sparton for me, but a 17# total pack weight for 5 days it sounds nice.
As everything gets lighter it takes less volume, lighter pack, etc. At 17# total you can go to a 4oz Cuben pack so you save another 20 oz from a GG mariposa plus.