How to improve quality of .3gp video
The problem is you don't have resolution for 700% upscale. ~~And aren't likely to find it in those tools~~ (strike that).

You can or may have already tried Video Enhancer. They claim to use Super Resolution to get the upscale possible. It doesn't suit all video sources. They have an AE plugin too.

If none of your searches for auto upscaling work then my recommendation is scale &amp; interpolate as high as you can accept the results, then apply a blurred background of the footage (like you see when online portrait orientation videos are broadcast on TV. Centre your footage so you have the video playing with the blurred background around 4 sides. see How to Edit Vertical Video Footage YouTube video for the effect.

Alternatively if the church still looks the same, create a sort of picture-in-picture. Shoot a wide 1280x720 video of the empty space matching the original footage camera moves as closely as possible. Drop your upscaled original footage in the middle. You may need to blur this background plate a bit. So if the original video upscales to only 352x288 that's the middle 40% of your frame (vertically).

If you have enough pans and tilts that show larger parts of the baptism space, I've seen reconstructed and enhanced super-8 footage that turned the footage into panorama-like canvases by stitching together individual frames and then assuming those backgrounds did not change. I have no idea how to do that. But it uses software like Hugin to find common parts of a frame to stitch photos together. Then a morph is applied to the outer parts of the frame when the camera moves. The morph is less jarring if you split the 1280x720 frame into 12 or 16 subframes and just morph each of those sections. Note it doesn't look realistic, it takes a bit of time to work out why the moving images look "wrong", but it gives an illusion of movement.

A final suggestion is to build a virtual interior of the church, so skin the walls, (and statues and stained glass) and run your upscaled old footage in the middle of this virtual space. Render the output. This is a VFX plate shot that AE can do.