Reliable battery charger / starter

Hello together! I have battery problems again. Batteries don’t seem to like me. This time at the Mazda. Yesterday evening he started, today it just clacked. The multimeter meant so 9.3V on the 12V 70AH Bosch battery. So I got stuck to the AEG charger. Battery could not be recognized. So I activated back and forth and emergency charge. Ne hour later 7.17V on the battery. I have now borrowed the charger from the professional. A Schumacher Speed Charg he. There seems to be something going on now, the 10V have already been cracked. I don’t know yet, of course, that the battery is not in the bucket after all (is actually only so 2 years old), but still, progress. Only in the future I wouldn’t want to be dependent on foreign help anymore, therefore the question, which charger can be recommended, that also with deep-discharged batteries will be finished? With this I could force the device to make fast charge of a “bad” battery n. My device has exactly the one button. Only it doesn’t seem to be Schumacher anymore, at least I don’t find anything. Greetings and thanks Marco