As well as the sound advice others have already given a solid option for a "fighty" magus is to make them a Verditius.
Upsides:
- You can prep enchanted items for combat in advance. Most magi will fall back on their tried and true favourite spells in a life-or-death situation anyway, this just fixes them into your equipment. Your advantages as a Verditius allow you to do this better than other magi so you punch above your weight even early on.
- You can make a number of charged items (potions, talismans, unguents, charged items can be framed in a lot of ways) to cover other bases. Again being a Verditius makes this more effective than for other magi.
- Either later on or maybe at the start if your saga allows it you'll be able to access mysteries such as Items of Quality that will allow you to improve your equipment further still. A quality sword with an extra +4 to "harm human and animal bodies" drastically increases the capability of a magus in combat before any spells are taken into account. You can also get quite thematic with these items - for example blackthorn has a Material bonus of +6 to "Guardians". A blackthorn shield of quality could enhance this quality and grant +6 to all defence rolls, but only when the bearer is defending someone else.
- Even if you don't learn these mysteries yourself if your character is a Verditius it's much easier to explain how they might commission some of these items from other Verditii.
Downsides:
- You need casting tools for formulaic magic so it's essentially useless in a fight. You will have to rely on spontaneous magic to deal with anything your items can't handle. A talisman and some attunements to improve your spontaneous magic is pretty vital (you'd be surprised what you can do with non fatiguing spontaneous magic with a good atunnement).
- You have to spend seasons in the lab occasionally actually making or improving items which isn't terribly compatible with a roving adventurer lifestyle.
- This character would not be well regarded by other Verditii if they spend all their time adventuring and making items for themselves instead of doing commissions and so on.
- To get the most out of the Verditius bonuses and mysteries you'll need to invest experience into getting at least moderately good craft and philosophiae skills so your arts and/or other skills will be slightly lower.
I've played a character like this and it's certainly interesting. Because you generally don't cast magic "in the field" but rely on items the vibe is less wandering wizard and more like one of those saga heroes who has all of his remarkable possessions described across 50 stanzas.