You gave Kodah a great life so don't beat yourself up over missing some days with him while you were sick, my condolences to you and your family during this time.
This is the hardest part about having a dog, they just don't live long enough and we never forget them when they are gone. Having gone through this several times in life it never gets easier but every one of them are worth it and will hold a special place in our hearts forever.
In 2020 I had to put down my Brizzy girl. (Tumors, lost like 20% of body weight) Then in 2021 our Little One Mancha... ugh... I'm pretty sure I watched her have a heart attack right beside me. (We knew she had a heart murmur. They told us that a couple years back when she had emergency surgery. Somebodies Lab was with them in the garage when they were doing their Halloween JAck-O-Lantern's in their garage, and their Lab ran out and attack her when my boy was walking by with her n the sidewalk, and they had to go in and clean up the the deep punctures. The suture ran across her back from shoulder to shoulder) And then not much later afte4r I witnessed that event which I assume ws heart attack (eyes wide open, panting short shallow breaths), she died in my arms.
I work from home too so they'd been my forever 24/7 companions for 15 and 15.5yrs respectively.
It's been about a year now since the Lil One's passed away, and each of the 3 of us will still occasionally comment about memories with them and be a lil "Sigh..." for a second or two here and there.