A 'trans woman' (man) or 'trans man' (woman) being in existence is not of itself a safeguarding issue.
Deceit, pretence, lying around issues to do with genitals and sex etc. is a huge safeguarding issue.
men in women's spaces is a safeguarding issue
drag acts which sexualise stories to very young children is a safeguarding issue
telling children that they can be any sex they wish is a safeguarding issue
recent changes to sex education are a safeguarding issue
encouraging and helping children to 'transition' is a safeguarding issue
giving children puberty blockers and destroying their physical health and natural development is a safeguarding issue
chest-binders being given out to girls is a safeguarding issue
telling children to do things and not tell their parents / agreeing to not inform parents is a safeguarding issue
having boys sharing girl's toilets at school is a safeguarding issue
having boys sharing girls' dormitories on school or activity trips is a safeguarding issue
having boys undress with the girls for sport is a safeguarding issue
having male leaders in the guides able to sleep with the girls is a safeguarding issue
having boys in the girls only guides is a safeguarding issue
having boys at a girls school is a safeguarding issue
and undoubtedly many more...