I hear you. Also raising 2 kids (ages 7 and 10) without extended family to help. You’re in a marathon, not a sprint. 3 things that have worked for me:

Getting on daily routine habits will create pockets of time for you and your wife to do your own thing. You can get creative here and feel the difference within a few weeks.

Reading stories to the kids before bed will give you a love-filled contrast to the Screens when your kids are older.

Lastly, finding a babysitter - even just once per month - was a game changer for me. Ask the bored parents at the indoor playground for a referral. Then you can take your wife out on a date - she’s probably burnt-out too :)