Will having long hair (as a man) cause me problems when travelling in Muslim countries?

I usually have a ponytail, but when my hair is down it's past my shoulders. I have been considering travelling to a few different countries such as Iran or Algeria, but I'd definitely prefer a general approach to take.

I know generally travelling in Muslim countries, women can wear headscarves and stick to long-sleeved tops and such. Will my hair be an issue? Should I wear as a bun to reduce its size? Are hats appropriate?

For reference: The Irish Department of Foreign Affairs has the following suggestion for travelling to Iran

Muslim culture

Iran is an Islamic Republic and Islamic practices and beliefs are closely adhered to in the country's customs, laws, and regulations. Common sense and discretion should be exercised in dress and behaviour.

Islamic codes of behaviour and dress are strictly enforced. Visitors should dress conservatively. Men should not wear shorts or sleeveless shirts; women must cover their head with a scarf and conceal the body’s contours by wearing a loose-fitting knee-length outer garment and trousers. Respect religious and social traditions to avoid offending local sensitivities.

There are additional dress requirements at certain religious sites. Women may be asked to put on a chador (a garment that covers the whole body except the face), before entering.

I have also similar concerns to this user wondering about Russia in terms of non-religious reception, more conservatism. Especially as in some of these countries homosexuality is illegal (e.g. Algeria) or have had several homophobic attacks.

Article saying Iran culture ministry bans "ponytails, mullets and elaborate spikes"