But you can use the ilanguageservice to get the installed languages

Or the domainservice to get the assigned domains for your current root

I have a piece of code spmewhere

There's no doubt a better way, but this works for me as a partial. It renders a dropdown but shouldn't be too hard to convert to buttons:-

@inherits Umbraco.Cms.Web.Common.Views.UmbracoViewPage<IPublishedContent>
@using System.Globalization;
@using Umbraco.Cms.Core.Models
@using UmbracoProject.Core.Models

@{
    var currentPage = Model.Url();
    var cultureList = Model.Cultures.ToList();
    var languagePickerLinks = new List<CultureLinkModel>();
    
    @foreach (var culture in cultureList) {
        var langName = CultureInfo.CreateSpecificCulture(culture.Value.Culture);
        
        var link = new CultureLinkModel {
            Url = Model.Url(culture.Value.Culture),
            Culture = culture.Value.Culture,
            LangName = langName.NativeName.Split(" ")[0]
        };
    
        languagePickerLinks.Add(link);
    }

    if (cultureList.Count > 1) {
        <div class="lang-switch">
            @{
                <select id="lang-switch"  asp-for="@currentPage" onchange="if (this.value) window.location.href=this.value">
                    @foreach (var culture in languagePickerLinks) {
                        <option value="@culture.Url">@culture.LangName</option>
                    }
                </select>
            }
        </div>
    }
}

The CultureLinkModel is just:-

namespace UmbracoProject.Core.Models; 

public class CultureLinkModel {
    
    public string? Url { get; set; }
    public string? Culture { get; set; }
    public string? LangName { get; set; }

}

Hope that helps.