Thanks for the report, but text “meshification” leading to terrible
topology is very old know issue, nothing new here, that is not
considered as a bug currently.
Blender dev don't want to correct this problem for now, so, the only way to have a good topology with text is to use another text generation, or to correct topology yoursef.
I'll give a partial answer, to solve the topology problems, but this solution is just based on somme topology problems on the T letter, and is didn't test all cases, so you'll maybe have to adapt this solution if it doesn't correct other topology problem or create other defects.
So the problem come from the bad topology generated from the conversion to mesh. Some 0 area faces are created, and with computation errors the normal of a 0 area face can be random, depending of the scale/position/rotation of the object and lead to bad result. In any cases, 0 area faces are bad for 3Dprinting.
A solution will be to use the degenerate dissolve after conversion, multiple times if necessary (until there are no edge or face removed), then triangulate the face again.
Mesh correction: Detailled explanation:
The convertion of a T-shape curve will result in a mesh with some 0 area faces.
Has we can see in this example the vertice is not connected to an edge.
Here is the 0 area face
The limited dissolve is not able to remove 0 area face, so use the degenerate dissolve in Mesh>Clean up>Degenerate dissolve (with all faces selected). Repeat this step until no edge or face are removed.
Now we can see that the corner vertice is connected to all edges.
The face is an ngon, so we have to triangulate the mesh if needed.
Using solidify anyway, the trick
Since the mesh will only be fixed after conversion, the solidify modifier on text objects can give strange results. I managed to obtained a stable rendering of solidify on text object by cheking both "Even thickness" and "High Quality normals". Not sure it will work in any case.
The good point about this is that since the mesh is not deformed by solidify normal miscalculations of 0 area faces, the conversion can be done with the modifier, and the Mesh correction explained before will work with the generated 3D model. It is still a better solution to clean before solidify when possible.