welders, the weld is often the "weakest link". The HAZ, Heat Affected Zone in stainless steels is often a problem. Aside from the reduced strength, the HAZ will also be subject to corrosion. And...there are, of course, many different stainless steel alloys. Some are available in "low carbon" grades specifically for welding applications. Some are heat treatable so, after welding, you can have a heat treat shop reheat treat the entire thing. This will restore both the strength and the corrosion resistance.
There are also mechanical designers and good mechanical designers. It may be challenging but, if you increase the section size (thickness) where the welds are, you reduce the stress on the HAZ just because there is more metal there to support the load. You could also try "overlay", make the weld as you have been but then strengthen it by welding another piece covering the first weld (like putting a long piece of tape over a short piece of tape on a xmas package. You might also be able to change the location of the weld so the weakest link is in a region of lower stress.
If you can go with Ti, you can get about the same strength with less weight. Of course this depends on exactly which Ti alloy you use (and there are many, some very high strength). And... welding Ti alloys can be more complicated than welding stainless steels. Unfortunately, the more sophisticated the alloy, the more likely you are to reduce strength in the weld.