Hi, new player here.
It is objectively time consuming to tech up as this faction. What is the advantage then, that i do not see?
1- Free upgrades with teching, you don't pay for lmg, panzerfaust and grenades.
2- Specialized units accessible to cover any particular situation. You have an easy access to Anti Infantry, Anti tank, light artillery, rocket artillery, medium tanks and medium tank destroyer, medium+ tanks (panther and Brumbar).
The only gap in Ostheer roster is a lack of light tank but since a year ago and allied light vehicule nerf, it is not anymore an issue.
Ostheer Commanders are more about how you want to complete your army than what gap do I want to fill and what gap I will not.
About Battle phases, with experience you'll remember costs and know when you can upgrade them. If you are new it is normal to have some issue with at the beginning.