in spite of practicing trading can be useless if there is no reliable support from a credible trading broker , because the broker always can affects the result of our trading with certainly.
True. Which regulators would you recommend?
Depends where you are from, what kind of offers you want/dont want, and level of 'unknown' risks you are willing to accept. Understand how regulators work in the international environment is a big step. Some dont offer protection for citizens/residents outside the regulating country, some will only allow you to submit a case in person and you msut attend the legal preceedings (can be costly if that country is the other side of the globe, and so on. Its really a key to understand how the regulators work both for the client side and broker side to make the choice thats best for you.
Cysec and FCA check out youtube 'BBC Documentary IronFX' is a good place to start in understanding that combination of regulators.
for NFA based check out the Famous FXCM that was even listed on NYSE. https://www.zerohedge.com/news/2017-02-06/alert-largest-us-forex-broker-fxcm-shut-down-and-permanently-banned-nfa
you can also check out at how their Asia business dealings differ form thsoe inside USA boarders.
What some of my experienced clients do when first registering with my broker is they test the deposit and WD systems and ask alot of specific questions that require a definite YES or NO response to reduce the 'grey area'.
With all that being said...i have clients that love running Arbi/HFT EAs with low regulated brokers (regulated from some group of islands, tax havens, etc) because they know how to use the broker's greed against them, but they do run into times they jsut flat cant WD money out. These kind of EAs typically dont work on more regulated environments so their same strategy doesn't work on all regulated brokers.