Men are naturally stronger than women in some way, so in those fields women will always be met with challenge from the overinflated neanderthal male ego. It's just nature and some things can't be changed, it's how we deal with them.
Under the new self id law you wouldn't be able to say any of this.
It is a transphobic comment.
It's transphobic because
a) you are making a distinction between men and women based on biology and not how a person feels - that's reductive.
Because, under the new law, a man isn't a person with greater strength in any area, a penis and testicles, etc, that will just be the body style that that particular person was born into.
And
b) you are asserting that 'we' will have to deal with 'them' which, not only distinguishes by biology, but denies your cis-privilege - which means that you are ignoring the privilege you have as a person whose internal gender aligns with your body style. E.g. you are a woman in a female style body rather than suffering as a woman born in a male style body.
For clarification:
There will be 2 body styles -
'male' - with eg penis, testicles, testosterone, greater physical strength, who are in charge and have poor impulse control around the 'female' body styled people.
and
'female' - with womb, ovaries, mentrual cycles, breastfeeding needs, less physical strength, who are predisposed to caring responsibilities and domestic chores who will acquiesce to the male body styled people.
Whereas women/girls:
Are sexy; like pink; like glitter; have long hair; wear make up; wear dresses; drink pretty drinks; play with dolls; paint their nails; bake cakes; flutter their eyelashes; enjoy being viewed sexually by men; simper and look to be rescued... (eg stereotypically female characteristics)
And men/boys:
Don't like pink; like blue; have short hair; don't wear make up; don't grow or paint their nails; drink lager/beer; climb trees; play rugby... (eg stereotypically male characteristics).
If a person displays 'woman/girl' characteristics, they are a woman/girl regardless of the body style they inhabit.
If a person displays man/boy characteristics, they are a man/boy regardless of their body style.
If they display characteristics from both categories in different contexts then they will be gender fluid (neither a boy/man nor a woman/girl).
This might sound like utter nonsense to you but that is the new status quo that the TRAs are campaigning for. Women are already losing their jobs/positions for questioning this or asking for clarification about how it will work in specific contexts. Organisations such as Mermaids are already issuing guidance materials for schools based on this model and, I believe, already being bought in to deliver training for staff based upon this model.