Clearly DS has a twin - who knew? He's 2 now and we're just coming out of the other side of over a year of fussiness. At his worst, he was very similar to your DS and refused anything I cooked in favour of pouches and jars. So frustrating, especially as weaning had started so well for us - but then he had a virus at 9 months and ate virtually nothing for a few weeks and we never got back on track.
A number of things helped for me. One was relaxing - I know it's a cliche but it really does help. DS would usually eat either Laughing Cow or peanut butter sandwiches. Not the most varied diet but nothing wrong with them. So if that was convenient, I'd offer him that.
Being at the childminder helped, where he ate almost everything on offer.
As did keeping mealtimes low-key and taking the pressure off - eg just me and him, rather than a bigger audience. I let him "pinch" my food as well if that works.
Things suddenly started to improve a couple of months ago. In addition to cereal, fruit, sandwiches, crisps/breadsticks, etc and sausages, he'll also eat chicken goujons, fish fingers, pasta, peas, cooked carrots, broccoli and various other things I could only have dreamed of earlier in the year.
So I'd suggest you stay calm, keep offering, and accept toddlers are fickle - today mine ate a nectarine, yesterday he wouldn't even look at one. Etc.
Things can change very quickly with this age group. I realised the other week that I can't remember when we last bought a pouch and once we've used the current one left in the cupboard, we won't be buying any more thank fuck for that. So hang in there and keep cool.