Certainly you have to adapt to the French way of doing things, and have realistic expectations (some non-French buyers expect a service they wouldn’t find in their home country, for example). I found that email, online enquiry forms - indeed, anything other than a face-to-face meeting* - is a waste of time
Fortunately you’re closer to Manche than a Brit-resident would be!
If you can identify a town where you think you’d like to live, you can look at immo websites and get a feel for any problems by checking their reviews.
Then you’ll need to visit the immobilier. Once they know you and that you’re serious, their attitude will usually change (that’s what we found). Until then, you’re a brick-kicker 
I suspect in the areas Brits like, immos are inundated with people filling in a wet afternoon by idle enquiries.
*One exception was an immobilière who was prepared to send us information following a phone call. But we already knew the town we were interested in and could speak knowledgeably about it.