Batch-Processing Pdfs for Speed and Compatibility?

I have a lot of pdfs with fancy imges which either (a) don't show on older devices, or (b) freeze slower devices, or (c) crash slower devices. I need to batch-process them to they work, converting jpeg2000 and other fancy images to jpeg, preferably compressing images, fixing font issues, etc.

I've used Ghostscript for this, before, but had a lot of trouble in Windows, especially with spaces in some source filenames.

I've tried using Pdf24. I can use Organize Pdfs > drop in a group of files > Save All > Custom (output profile) > PDF 1.4 and Good quality under General > Continue > set an output folder > check the output files.

I still have to set the output profile each time. I've set it to PDF 1.4 in the settings, but it always reverts to PDF 1.7. Is there a way to set a persistent output profile?

I still have to set the output folder each time, too. I've created a special folder for this, but I have to navigate through the tree to reach that folder each time. Is there a way to, inseally, create the new files in their source folders or, failing that, set a persistent output folder?

I still have to manually rename each file afterwards, to note the processing and to distinguish it from the original. Is there a way to add an appropriate label to each output file? (such as [inputname]-pdf24.pdf instead of [inputname].pdf)?