My comment is made from the background of someone who has led the effort of bringing software …

My comment is made from the background of someone who has led the effort of bringing software development in-house, building a 20-odd FTE dev team, and is still leading it 3 years in. I'd not bring everything in-house at once unless you really have to. Your fear that the devil is in the details is very much justified (I have stories, boy, do I have stories ...). However, in your position I would definitively start building a dedicated tech team. That allows you to start developing real solutions to solve pain points in a way that feels less like "filling the gaps" and more like "the first steps towards a better future". It also may make you a better, more informed customer which may perhaps help with your current vendor as well. It also gives you something to fall back on if the proviable shit really hits the fan with your current vendor. Do not underestimate the importance of product management. Product management drives your development team. If you now use a basically off-the-shelf product, this is likely taken care of for you. Or not, given you describe the vendor as stagnant. …