For someone like you, who knows what they are doing, but will also put a machine through heavy duty use, Bernina 1008. Hands down. Technically they are no longer being made by Bernina, but you can find them available online. (And yes, they will be expensive, even used. But they are worth every penny.)
This is the model we used in the costume shop at WKU, and believe me the college kids beat the crap out of them, and they just kept ticking. Never gave me a lick of trouble, aside from an occasional thread nest when some freshman would put a bobbin in wrong. They are non-computerized, all mechanical. All solid steel parts, no plastic in the guts to break down. I have literally sewn through wood with them (paint stirrers, don’t ask why). Because they got such heavy use from novices, we had them serviced once a year at the end of the school year to be on the safe side. But seriously, I never had a single one break down in the 6 years I worked there. Never once needed to take one in to be serviced mid year.
They will easily barrel through flat felled denim seams, corset coutil, and (provided you use the right needle and foot), will also gather lightweight silk or do a rolled hem with chiffon without a pull or hinky stitch.
https://www.bernina.com/en-US/Machines-US/Series-Overview/BERNINA-Classic-Series/BERNINA-1008
The first set I had in my shop was bought in 1997 or 1998, and because schools require you to put in a request for new items sometimes several years in a row before they will replace equipment, we put in a request for new machines in 2009 even though they were running perfectly, expecting that we would be waiting about 4 years or more before they approved us. By some miracle we got approved that year, and got the 1008’s which were the newer version of our same model from 1997. Exact same features, knobs, dials, etc. Just a slightly different logo. We found them selling for $1299 in 2009, but got an educational discount from a vendor so we paid $749 each for 8 of them. We sold off some of the older machines so we could afford a new washing machine, and so many people in the Fine Arts Center wanted them, even 12 years old and beaten by college kids, we had to turn folks away.
…Sewing through layers of paper, layers of fabric, denim, wool, cardstock, cardstock and fabric, all kinds of bulky layers 
It has a few “fancy” stitches but I mostly stick to straight and zig-zag. Also has a needle threader thingy that makes my life a little easier 
