Looks good but If using the known Electrum Server will make me use 8Gb RAM , 200GB SSD , 2 CPUs VPS as mentioned above by mocacinno then how much ElectrumX is supposed to take ?
3GB RAM is ample. 40GB of disk space should give enough to last another year or two of blockchain growth. The current dB is a little under 20GB. Dual core is perfect - python only uses one core in general.